Russian diplomats panned this week's security talks with the U.S., NATO and other European countries after the final set of negotiations on Thursday, telling reporters that Vladimir Putin will be briefed on the "really disappointing" state of affairs before deciding "next steps."

Why it matters: The diplomats wouldn't say what Russia would do if NATO declined to provide legal guarantees that it will not expand east or admit Ukraine as a member. But officials have warned all week that Russia will not hesitate to "eliminate unacceptable threats to our national security" if diplomacy fails.

The big picture: More than 100,000 Russian troops have massed on the border with Ukraine, raising fears that Putin will further invade his vulnerable neighbor in an effort to stop Kyiv's drift to the West.

• "It seems the risk of war in the OSCE area is now greater than ever before in the last 30 years," Zbigniew Rau, the Polish chairman of the Organization for Security and Cooperation in Europe, said at the outset of Thursday's meeting in Vienna.
• His comments echoed those of NATO Secretary-General Jens Stoltenberg, who warned after the meeting of the NATO-Russia Council on Wednesday that the alliance is preparing for the "real risk of a new armed conflict in Europe."
• Michael Carpenter, the U.S. ambassador to the OSCE, said at a press briefing Thursday: "We're facing a crisis in European security. The drumbeat of war is sounding loud and the rhetoric has gotten rather shrill."

Driving the news: "I do not see reasons to sit down in the coming days, to gather again and start these same discussions," Russia's Deputy Foreign Minister Sergei Ryabkov, who led the U.S.-Russia bilateral talks on Monday, said in a TV interview.

• Russian Foreign Minister Sergey Lavrov said the U.S. has promised a written response to its demands, which Moscow will review before deciding the path forward.
• Kremlin spokesman Dmitry Peskov also condemned U.S. legislation introduced by Senate Democrats this week that would impose a cascade of sanctions — including on Putin himself — if Russia invades Ukraine.
• Sanctioning a head of state "is an outrageous measure that is comparable to breaking off relations," Peskov said, calling it an "extremely negative" gesture against the backdrop of ongoing negotiations.