Ukrainian and Russian negotiators were poised to meet Friday for the first direct peace talks between their nations since the beginning of the war, after days of confusion and theatrics.

The negotiations are not expected, even by foreign leaders like President Trump who called for them, to yield significant results. But the meeting itself is a win for President Vladimir V. Putin of Russia, who refused to agree to a battlefield cease-fire that Ukraine and almost all of its Western backers had sought as a precondition for talks.

Last weekend, Mr. Putin announced that he would send a delegation to Istanbul for negotiations. Mr. Trump chimed in that he supported the idea. The Russians arrived in the Turkish city and announced on Thursday that they were ready to talk.

The situation put pressure on President Volodymyr Zelensky of Ukraine, who had tried to get Mr. Putin to meet him personally in Turkey for negotiations and also attempted to get Mr. Trump to come.

Mr. Zelensky questioned Russia’s seriousness and the way the talks were being organized. But he agreed to send a Ukrainian delegation led by his defense minister, saying he was doing so out of respect for Mr. Trump and the Turkish president, Recep Tayyip Erdogan.

“There is no time of the meeting, there is no agenda of the meeting, there is no high-level delegation,” Mr. Zelensky said Thursday after meeting with Mr. Erdogan. “I think Russia’s attitude is unserious.”