Key points
- Mines swept away by floods 'pose grave danger for decades'
- Alex Crawford: 'There are land mines floating here'
- Satellite images reveal submerged town after dam burst
- Dam destruction benefits our army, says Russian-backed official
- Sean Bell:New phase of war 'brewing'
- Watch: Panic at evacuation point as sound of shelling rings out
- Your questions answered:Could Iran start giving tanks to Russia?
- Got a question about the war? Ask our experts
- Live reporting by Niamh Lynch
Your questions answered: Is US support a dealbreaker?
Our defence experts and senior correspondents have been taking readers' questions about the war.
The latest comes from Anton, who asked whether, in the event of Donald Trump winning in 2024 and withdrawing US support, Ukraine's remaining allies could see it through to victory.
Military expert Sean Bell had this to say on the matter...
Since the war began, the Biden administration and the US Congress have directed more than $75bn in assistance to Ukraine, which includes humanitarian, financial and military support.
As the second-biggest donor, the UK has committed £4.6bn in military assistance to Ukraine (£2.3bn last year and a commitment to match that funding this year). As of February this year, military aid was donated by a variety of EU institutions and 45 sovereign countries.
Although there are many nations supporting Ukraine, the US is by far the biggest donor of both financial and military aid. Therefore, if the US decided to stop supporting Ukraine, it would leave a significant gap that would be very hard for others to fill.
However, the world of politics rarely makes binary decisions, so it is very unlikely that any nation would halt the supply of military aid overnight. All nations have domestic priorities that have had to be compromised to support Ukraine, and most will struggle to maintain the same level of support for Ukraine in perpetuity.
But Russia will also struggle to maintain the level of commitment to its invasion, which is why the forthcoming Ukrainian spring offensive has such strategic importance.
Politically, the US would probably welcome Europe taking a greater leadership role in the Ukraine conflict; it is on the European continent, and the US has encouraged European members of NATO to increase their level of domestic defence spending closer to the 2% of GDP target.
This could leave the US to focus on the Indo-Pacific region and encourage a more equitable international contribution to global security.
Regardless, had the West not provided military support for Ukraine, it is very likely that Russia's invasion would have been considerably more successful, and a Russian victory in Ukraine would have profound implications for global security.
Therefore, notwithstanding the costs and implications, the international community is very likely to continue to support Ukraine over the medium to long term, though we can expect to see individual nations review their specific level of support along the way.
How could a chemical used in fertiliser influence the course of the war?
By Diana Magnay, Russia correspondent
A few hours before a massive explosion destroyed the Khakovka dam in southern Ukraine, a pipeline built to transport one of Russia's major exports, ammonia, was hit by shelling 400 miles to the north.
The governor of the Kharkiv region, where the pipeline crosses from Russia into Ukraine and then makes its way down to the Black Sea port of Pivdennyi, said leakage was not above the "allowable norm" but video from Russian social media channels shows a dense white cloud churning over an unidentified building and hanging low in woodland.
Russia blames "Ukrainian saboteurs"; Ukraine blames Russia. No surprises there.
Ammonia matters to Russia.
It is used to make fertiliser and the re-opening of the Tolyatti-Odesa pipeline - which has transported Russian ammonia through Ukraine and out to world markets since the 1970s, though not since the outbreak of the war - is a crucial pre-condition, Russia says, for any extension of the Black Sea Grain deal which expires on 17 July.
The UN has warned of its concerns at the slowdown in grain exports from Black Sea ports over recent months given the "spectre of food inflation and market volatility" lurking in all countries.
Talks resume in Geneva this Friday.
Ukraine's wheat harvest is happening now.
That grain will need to be exported and world food prices are currently hostage to meagre sixty day extensions and Russian brinkmanship.
The damage to the ammonia pipeline gives the Kremlin extra bargaining power as it pushes for other demands such as reconnecting the Russian Agriculture Bank to SWIFT and further sanctions relief.
This crucial grain deal, not yet one year old, hangs in the balance as mysterious pipeline explosions once again play their part in geopolitical machinations.
Panic at evacuation point at sound of incoming fire
Our special correspondent Alex Crawford is at an evacuation point in the city of Kherson in southern Ukraine where residents have been forced to run and take shelter in buildings as the sound of incoming fire rang through the air.
Crawford says it was difficult to judge how far away it was, perhaps 500m.
It was "enough to scare everyone in the vicinity", she says.
Soldiers have told Crawford that at least one person has been killed at a flood evacuation points in Kherson.
She says there have been "a lot of incoming strikes at multiple areas in the city including more than one evacuation area" and "a number appear to have been injured".
Devastation in Kherson as aid workers rush to evacuate people and pets
More pictures of the devastation caused by the flooding have emerged as aid workers rush to evacuate stranded people and pets.
The region is home to many elderly people whose beloved pets have provided comfort and company as the 15-month war raged on.
UK 'playing our part' in Ukraine flooding aid efforts - Rishi Sunak
Rishi Sunak has told reporters in Washington the UK is "playing our part" to support aid efforts after the dam flooding.
Speaking in Washington DC, the prime minister said: "We're still establishing definitively the cause of the attack on the dam in Ukraine.
"But I want people to know that we are playing our part to support the Ukrainians in their response.
"We've provided resources to the United Nations and the Red Cross in advance, anticipating incidents like this.
"This is an appalling act and hundreds of thousands of people are being affected by it. We'll continue to provide support for Ukraine."
Mr Sunak also pushed back against recent comments made by former Russian president Dmitry Medvedev that the UK's military involvement in Ukraine made it a Russian target.
"Nobody did anything to justify that Russia decided to unilaterally invade another country, caused an enormous amount of suffering to its people."
He added: "The values that we are defending - democracy, freedom, the rule of law - are universal. They apply to us all.
"And when they are challenged in the way that Russia has challenged them, it's right that we come together to defend them."
Watch: 'There are floating land mines here'
Our special correspondent Alex Crawford reports on the flooding in Kherson, where sewage, debris, oil and floating landmines are all threats to rescue efforts.
She also speaks to a German firefighter who is one of the few foreign rescue workers in the area...
Russia urges UN judges to throw out cases relating to 2014 Crimea invasion and 2022 rebel arming
Russia has urged judges at the United Nations' highest court to throw out a case brought by Ukraine against Moscow.
The case relates to the 2014 annexation of the Crimean Peninsula and the arming of rebels in eastern Ukraine before Russia's invasion in February 2022.
"We appear before you today in order to demonstrate that Ukraine's application must be dismissed because it is without any legal foundation. Nor does it have any factual evidence to back it," Russian ambassador to the Netherlands Alexander Shulgin told judges at the International Court of Justice.
Ukraine's lawyers said as hearings in the case opened on Tuesday that Russia bankrolled a "campaign of intimidation and terror" by rebels in eastern Ukraine starting in 2014.
It also sought to replace Crimea's multiethnic community with "discriminatory Russian nationalism", the lawyers said.
Ukraine filed the case in 2017, asking the court to order Moscow to pay reparations for attacks and crimes including the shooting down of Malaysia Airlines flight MH17 by a Russian missile fired from territory controlled by Moscow-backed rebels.
All 298 passengers and crew were killed in the July 2014 attack.
The Ukrainian government alleges that Russia breached two treaties: the International Convention for the Suppression of the Financing of Terrorism and the International Convention on the Elimination of All Forms of Racial Discrimination.
The hearingsare expected to wrap up next week, after which judges will take months to reach a decision in the case.
Zaporizhzhia nuclear power plant 'reliably protected', Russia says
The head of Russia's state nuclear energy company Rosatom said that the Zaporizhzhia plant is "reliably protected".
The presence of the International Atomic Energy Agency provides additional protection, the state-owned news agency TASS reported.
The dam burst caused huge anxiety about the safety of the plant as it draws cooling water from the Kakhovka dam.
The plant has been under Russian control since March last year.
New phase of war is 'brewing'
Our military analyst Sean Bell has been speaking about the long-term military implications of the dam burst.
"From a Ukrainian perspective, there was a very limited amount to be gained by this flooding but from a Russian perspective what they have done is sealed off the flanks of an attack," he said.
"Ukrainians will find it more difficult to attack and it has distracted the Ukrainians."
But he said when the flooding dries up, it could provide a front for the Ukrainian offensive.
"Ukraine will have known this dam was going to be blown at some stage. It's been rumoured to have been mined ever since the start of the war.
"The Russians have played this card [but] within a matter of weeks the area will have dried out and therefore it opens up that flank potentially to attack again.
"So whilst it's really bad news and [there are] long-term implications for Ukraine, for the locals, for flooding, for fresh water, militarily now that it's taken that card off the table, the waters will dry, the land will dry and that therefore will open up a front that Ukraine might not have expected to have quite this early."
Bell also said he believes Ukraine is in the second phase of its offensive and are testing Russia's strength on the frontline.
"We expect them to go rushing over the start line [but] almost certainly the first phase of this was a targeting of Russian logistics, the second phase is to test the whole of the frontline.
"It's a 1,200km frontline. If Russia were to spread its forces evenly, it's one every six metres. It's not very many, they're not very deep defences.
"What Ukraine is doing at the moment is it's testing the Russian defences and seeing where they give.
"Russia will be holding forces in reserve to pack wherever Ukraine breaks through so Ukraine wants to test slowly - that's the phase we're seeing at the moment.
"When they make a breakthrough, then I think we'll start to see the main offensive but to date we've not seen the tanks, we've not seen the thrust, the punch that we're expecting.
"But it's brewing, the war is coming."
Zelenskyy chats with elderly survivors after dam collapse
As we reported earlier, President Zelenskyy has visited the Kherson region in eastern Ukraine after the collapse of the Kakhovka dam.
The photos show the president meeting elderly women in a temporary shelter after being evacuated from the flooding.
Mr Zelenskyy also met local officials to discuss the extent of the destruction and plans to compensate residents.