US President Donald Trump said Wednesday that his envoy Steve Witkoff's meeting with Russian leader Vladimir Putin was"very productive" and made "great progress," but did not clarify whether he would implement new sanctions.

The meeting took place in the Russian capital two days before the expiration of an ultimatum issued by the White House leader to Russia to suspend its offensive in Ukraine, under threat of increased sanctions on Moscow and secondary sanctions on countries that buy Russian hydrocarbons.

"Witkoff just had a very productive meeting with Putin. Great progress has been made! I then briefed some of our European allies on the details. We all agree that this war must end, and we will work to achieve that goal in the coming days and weeks," Trump declared on his social media platform, Truth Social, without giving further details.

Shortly before, US Secretary of State Marco Rubio confirmed that Witkoff was returning to the United States after speaking with the US envoy by phone and postponed details until later.

"We'll have further conversations throughout the day, and I think there will be some announcements soon. Maybe positive, maybe not, we'll see," Washington's foreign minister told reporters.

After Putin and Witkoff met in Moscow, the Kremlin described the talks as"useful and constructive" but refused to "follow up with anything more substantial" until Trump received information on the matter.

A senior US official cited by international agencies indicated that, despite the progress noted by Trump, the United States still plans to implement secondary sanctions on Friday, targeting countries that purchase goods from Russia, particularly oil and weapons.

After pressure from Trump, who even threatened countries importing Russian products with 100% trade tariffs, former Russian President Dmitry Medvedev, currently vice president of the Russian Security Council, considered each new ultimatum"a threat and a step towards war."