Undercutting a weekend of European diplomacy, President Trump on Sunday implored Ukraine to accept a Russian proposal for direct talks rather than insist on a cease-fire first — as had been laid out in a plan announced a day earlier by European leaders during a visit to Kyiv.

The leaders of France, Germany, the United Kingdom and Poland had set a deadline of Monday for Russia to accept a 30-day cease-fire — one initially proposed by the Trump administration — or face additional sanctions.

When President Vladimir V. Putin of Russia made a counteroffer of direct talks, without mentioning a cease-fire, France and Germany rebuffed the proposal. Mr. Trump’s envoy to Ukraine in the talks, Gen. Keith Kellogg, had also earlier Sunday said Russia should halt hostilities as a first step in negotiations.

But Mr. Trump wrote in a post on Truth Social that “President Putin of Russia doesn’t want to have a Cease Fire Agreement with Ukraine.” The Russian leader, he wrote, wanted direct talks to be hosted by Turkey instead. “Ukraine should agree to this, IMMEDIATELY,” Mr. Trump wrote.

Earlier in the day, Mr. Zelensky responded cautiously to the Russian counteroffer of direct talks, insisting again on a halt in the fighting. After Mr. Trump’s post, Mr. Zelensky added a new twist to the diplomatic brinkmanship, saying he would personally attend negotiations. Mr. Putin, in suggesting direct talks, had not proposed a presidential meeting.

Mr. Zelensky’s declaration in a post on X did not clarify whether his participation would depend on Russia first accepting a cease-fire, but he called again for Russia to halt hostilities to allow for diplomacy.