Ukraine is ready to sign a minerals deal with the United States, Ukrainian President Volodymyr Zelensky told UK media on Sunday.

"The agreement that's on the table will be signed if the parties are ready," he told a late-night huddle with some UK media after a landmark summit in London.

The deal, which was supposed to be a step towards helping to end the conflict in Ukraine, fell through on Friday after a televised Oval Office clash with US President Donald Trump.

"It is our policy to continue what happened in the past, we're constructive," Zelensky said, quoted by the BBC.

"If we agreed to sign the minerals deal, we're ready to sign it."

Zelensky reiterated that Ukraine would not concede any territory to Russia as part of a peace deal. He said he was still willing to sign a minerals deal with the US and described a discussion on Sunday with European leaders to send a draft peace plan to the US as a key development, reports Reuters.

In an extraordinary meeting that was broadcast live on Friday, Trump accused Zelensky of being ungrateful for U.S. aid, of showing disrespect to his country and of risking World War Three, casting into doubt Washington's ongoing support for Ukraine in its three-year-long war with Russia.

Zelensky spoke to reporters at a London airport after a summit with European leaders in London on Sunday. While he seemed in good spirits and thanked European countries for their support, the Ukrainian leader was careful to balance his dismay with the events of Friday's Oval Office meeting with a clear desire to keep talking with Washington.

"We agreed upon signing it; and we were ready to sign it. And honestly I believe the United States would be ready as well," he said.

Trump had sought to cast the minerals deal as a way for Ukraine, which is home to a trove of lithium deposits and rare earth minerals, to repay the U.S. for its billions of dollars in aid.

While Zelensky sought to avoid any further antagonism of the U.S., saying he did not want to go over what had happened, he was more forceful on any future ceasefire deal, saying Ukraine would not hand sovereignty of occupied Ukrainian land to Russia.

"Everyone needs to understand that Ukraine will never recognise whatever is occupied by Russia as Russian territories," he said.

"We hope that these security guarantees will make it 100% impossible to give Russia the opportunity to come with another aggression".

Zelensky said there had been contact between Kyiv and Washington since Friday's bust-up, although not at his level, and asked if he had considered resigning, he showed no sign of wavering.

"As regards resignation, if I'm to be changed ... to change me it will not be easy because it is not enough to simply hold elections. You would need to prevent me from participating in the elections and it will be a bit more difficult."

Some Republican leaders had suggested that Zelensky needed to resign after Friday's meeting with Trump.

Zelensky repeated again, however, that if Ukraine was granted NATO membership, he would have fulfilled his mission.