US President Donald Trump has presented a new, shorter deadline for Russia to agree to a ceasefire over the war in Ukraine of "ten or 12 days" from Monday.

President Trump said there was "no reason" in waiting any longer as no progress towards peace had been made. Ukrainian President Volodymr Zelensky called the intervention "extremely significant".

Two weeks ago, Trump said President Vladimir Putin had 50 days to end the war or Russia would face severe tariffs.

Speaking at a news conference in Scotland, Trump said he would confirm the new deadline on Monday or Tuesday, but reiterated the threat to impose sanctions and secondary tariffs on Moscow.

Zelensky thanked Trump for the adjusted deadline, saying it came "right on time" in a social media post on X. He praised the US president's "clear stance and expressed determination" on "saving lives and stopping this horrible war".

Earlier in July he said those would amount to 100% tax imposed on any country that trades with Russia.

This would make the goods so expensive that US businesses would likely choose to buy them cheaper from elsewhere, resulting in lost revenue for both Russia and the country that trades with it.

Speaking after a meeting with UK Prime Minister Keir Starmer in Scotland, Trump again expressed his disapproval at Putin's actions in Ukraine, where war rages on three and a half years into Russia's full-scale invasion.

While he refused to say whether he felt Putin had been "lying" to him, Trump highlighted the contrast between the Russian president's rhetoric during their one-on-one conversations and the missiles "lobbed" on Ukrainian cities on a near-nightly basis.

"We were going to have a ceasefire and maybe peace... and all of a sudden you have missiles flying into Kyiv and other places," Trump lamented, adding that he thought negotiations would be possible but that it was now "very late down the process".

"I say, forget it. I'm not gonna talk anymore. This has happened on too many occasions and I don't like it," he said, though he also insisted that he and Putin always got along very well.

Trump also said he was "no longer interested in talks" - a line which instantly flashed up on major Russian media outlets.

Putin has never commented on the timeframe. When the initial 50 days deadline was first announced, Kremlin spokesman Dmitry Peskov merely labelled it as "very serious" but added that Moscow needed time to analyse it.

Referring to the latest developments on Monday afternoon, Russian MP Andrey Gurulyov said Trump's ultimatums "didn't work anymore... not on the front line, not in Moscow" and that Russia had the force of its "weapons, principles and will".

When Trump first mentioned shortening the deadline Ukrainian presidential chief of staff Andriy Yermak praised him for "delivering a clear message of peace through strength" and added that Putin "respects only power".

In recent months Russia has ramped up its attacks on Ukraine, launching swarms of drones and missiles on cities while pressing on with its summer offensive in the east of the country.

Three rounds of ceasefire talks between Russia and Ukraine hosted by Turkey have resulted in thousands of prisoners of war being exchanged - but no real progress was made towards agreeing a ceasefire.

After three and a half years of bloody conflict, it is unclear how the two sides could possibly reach an agreement to stop the fighting within 12 days.

All of Russia's preconditions for peace - including Ukraine becoming a neutral state, dramatically reducing its military and abandoning its Nato aspirations - are unacceptable to Kyiv and to its Western partners.

At the last week's round of talks, which lasted barely an hour, Peskov said a "breakthrough" in negotiations was "hardly possible".