Russian and NATO ended four hours of talks over Ukraine with no resolution on Wednesday, in the second round of high-stakes discussions in Europe aimed at preventing Moscow from invading Ukraine again. The U.S. and Russia held bilateral talks in Geneva on Sunday and Monday, and Ukraine will enter the talks for the first time on Thursday, when Russian diplomats sit down in Vienna with the Organization for Security and Cooperation in Europe. Ukraine is a member of the OSCE but not NATO, yet.

Russian President Vladimir Putin, who has amassed about 100,000 troops on the Ukraine border, is demanding that NATO guarantee Ukraine and Georgia never join the alliance. Moscow is also seeking “the removal of all NATO military infrastructure installed in Eastern European countries after 1997, effectively attempting to rework the consequences of the Soviet Union’s collapse in 1991, which left Russia weakened for years,” The Washington Post reports. 

NATO Secretary General Jens Stoltenberg said after Wednesday’s meeting in Brussels that all 30 members of the security alliance agreed that NATO “cannot discuss some core principles” on Russia’s orders, notably the bloc’s “open door” policy, that countries should decide their own foreign policy and geopolitical alliances. He said the Russians were noncommittal about NATO’s counterproposal for more talks on arms and troop limits.

“There is a real risk of a new armed conflict in Europe,” Stoltenberg said. “We are clear-eyed. So we also conveyed a message to Russia that if they use military force there will be severe consequences; economic sanctions; political sanctions.” 

U.S. Deputy Secretary of State Wendy Sherman said the Russian’s stated fears for its own security don’t make sense, given that “they are a powerful country” with a vast nuclear arsenal and a permanent seat on the United Nations Security Council. “The fact that they feel threatened by Ukraine,” which is none of those things, “is hard to understand,” she added. 

“Other officials and diplomats said that Russia used the session in part to air a litany of old grievances, including over NATO’s involvement in the war in Yugoslavia in the 1990s, and also its air bombing campaign in Libya in 2011 that contributed to the death of the dictator Moammar Gadhafi,” Politico Europe reports. “Stoltenberg said that NATO allies from the former Yugoslavia had pushed back directly against the Russian allegations.”