U.S. President Donald Trump renewed a threat on Friday to impose sanctions on Russia if there is no progress toward a peaceful settlement in Ukraine within two weeks, signaling frustration at Moscow a week after his meeting with Russian President Vladimir Putin in Alaska.

"I'm going to make a decision as to what we do and it's going to be, it's going to be a very important decision, and that's whether or not it's massive sanctions or massive tariffs or both, or we do nothing and say it's your fight," Trump said.

Ukrainian President Volodymyr Zelenskyy, meanwhile, said on Friday that Russia was doing everything it could to prevent a meeting between him and Putin, while Russia's foreign minister said the agenda for such a meeting is not ready.

Trump had said he had begun arrangements for a Putin-Zelenskyy meeting after a call with the Russian leader on Monday following their Alaska meeting on August 15.

"The meeting is one of the components of how to end the war," Zelenskyy said on Friday at a press conference in Kyiv with NATO Secretary General Mark Rutte. "And since they don't want to end it, they will look for space to [avoid it]."

Russian Foreign Minister Sergei Lavrov told NBC on Friday that Russia is prepared to show flexibility regarding issues proposed by Trump during the Alaska talks. Lavrov noted that a Putin-Zelenskyy summit has not yet been scheduled; however, Putin remains ready for talks once the agenda is finalized.

Asked for his response to Lavrov's comments and the next steps, Trump told reporters: "Well, we'll see. We're going to see if Putin and Zelenskyy will be working together. It's like oil and vinegar a little bit."

'He may be coming'

Trump had taken sanctions off the table in preparation for his summit in Anchorage with Putin. "I'm going to sign this for him. But I was sent one, and I thought you would like to see it, it's a man named Vladimir Putin, who I believe will be coming, depending on what happens. He may be coming, and he may not, depending on what happens," Trump said.

During a visit to a nuclear research center on Friday, speaking on Russia-U.S. relations, Putin noted that bilateral ties had "seen light at the end of the tunnel" since Donald Trump took office. He described their Alaska meeting as "highly candid," adding it marked "only the beginning of a full restoration of relations." Putin emphasized that the future of Russia-U.S. relations depends on Washington's leadership, expressing Moscow's readiness for full bilateral reconciliation.

Russia has maintained its longstanding demand for Ukraine to give up land it still holds in two eastern regions while proposing to freeze the front line in two more southerly regions Moscow claims fully as its own, and possibly hand back small pieces of other Ukrainian territory it controls.

Zelenskyy has meanwhile dropped his demand for a lengthy ceasefire as a prerequisite for a leaders' meeting, although he has previously said Ukraine cannot negotiate under the barrel of a gun.

At the press conference with Rutte, Zelenskyy said they had discussed security guarantees for Ukraine. He said Ukraine aims to secure "Article 5-like" guarantees, similar to Article 5 of the North Atlantic Treaty. According to Zelenskyy, negotiations between Ukraine, Europe and the United States on the specific content of the security guarantees are ongoing.

Zelenskyy and Rutte also discussed weapons deliveries to Ukraine coordinated under the Ukraine Prioritized Requirements List, proposed by NATO and the United States, as well as joint efforts aimed at ending the Russia-Ukraine conflict.

(With input from agencies)