UK Prime Minister Rishi Sunak has said that Russia would have hit "new lows" if it turns out that Moscow is responsible for the destruction of a crucial dam.

While on his way to Washington, Rishi Sunak told reporters that intelligence agencies are yet to make a definitive judgement about Putin’s involvement in the "appalling attack" on the Nova Kakhovka dam.

If it's intentional, it would represent, I think, the largest attack on civilian infrastructure in Ukraine since the start of the war, and just demonstrate the new lows that we would have seen from Russian aggression," Sky News quotes Sunak.

"Attacks on civilian infrastructure are appalling and wrong.  We've seen previous instances of that in this conflict so far, but it's too early to say definitively," Sunak noted.

The prime minister also said that the UK's immediate response to the attack was to provide humanitarian aid.

"We had already put resources and funding in place to support both the UN and the Red Cross to respond to situations like this," he said. "And they are now being able to divert those resources to particularly help humanitarian response and the evacuation in this area as a result of what's happened," Sunak added.

As it was at the G7 meeting in Japan, in their bilateral talks in the Oval Office on Thursday, the UK and US leaders will centre their discussions on the matter of Ukraine and the ways Western allies can best support Kyiv in its fight against Russia.

"One of the things the prime minister and President Biden will discuss is how we can sustain the huge level of global support for Ukraine while providing them with the capabilities they need, including air defence," the prime minister's spokesperson said ahead of the trip.

US National Security Council Strategic Communications Coordinator John Kirby has said that Washington is continuing to assess the situation following the blowing up of the Kakhovka Hydroelectric Power Plant in southern Ukraine.

Kirby said that Washington is ready to help Kyiv overcome the consequences of the disaster, including through international humanitarian organisations.