US envoys Steve Witkoff and Jared Kushner arrived in Moscow on Thursday to meet President Vladimir Putin following two days of US-mediated talks in Abu Dhabi that produced a prisoner exchange but no peace breakthrough.

The Abu Dhabi negotiations, which ended Wednesday, were the first trilateral talks between Russia, Ukraine and the United States in nine months. Both sides agreed to a large-scale exchange of prisoners of war, though neither gave a concrete figure. Kushner described the discussions as "substantial" and "quite tough," adding that there was a lack of trust between the parties and that territory "will be the hardest" issue.

Ukrainian President Volodymyr Zelensky said in Dublin that a "window of opportunity" exists to end the war by the end of the year. He has little faith in the outcome of the Americans' negotiations with Putin. He said much depended on "the will of American side to pressure on Russia or not." He rejected US pressure to surrender territory in Donbas, stating: "They think that to stop this war, we have to give up our territory. It's impossible to talk this way with us."

Senior Democratic lawmakers sharply condemned the envoys on Wednesday. Congressman Gregory Meeks, Congressman Adam Smith and Senator Jack Reed accused Kushner and Witkoff of undermining Ukraine while advancing Russian interests. They wrote: "They and Trump are working for Putin, not for the benefit of the people of the United States." They warned that the envoys' actions threatened NATO and condemned pressure on Kyiv to surrender sovereign territory, including fortified defensive positions in Donbas.

The US has asked Russia to propose a new security agreement with Europe as part of efforts to end the war, wanting Moscow to outline security demands alongside steps to reduce tensions. Kushner said he hoped Putin would give his "blessing" for European representatives to join future peace talks. Russia opposes European participation, while European governments remain skeptical of the proposal. Zelensky welcomed a "change in tone" from the US on Europe's inclusion.

After Moscow, Witkoff and Kushner plan to fly to Dublin to meet Zelensky, who is attending a gathering of European leaders there. NATO Secretary General Mark Rutte said the talks showed the US, Ukraine and Europe were "aligned and united." Russian chief negotiator Vladimir Medinsky said Russia ruled out exchanging territory and would continue expanding its buffer zone along the Ukrainian border.