By Ken Bredemeier

WASHINGTON/MOSCOW - Top U.S. and Russian diplomats expressed little optimism Sunday that tensions between their countries would be eased at high-level discussions this week in Europe over Moscow's massive troop buildup along its Ukraine border and Russian demands for Western security guarantees.

"It's hard to see we're going to make any progress with a gun to Ukraine's head," U.S. Secretary of State Antony Blinken told CNN's "State of the Union" show.

"We're going to listen to Russia's concerns" about NATO military exercises in central and eastern Europe, Blinken said, but added, "They're going to have to listen to ours" about the 100,000 troops Russia has amassed along Ukraine's eastern flank.

Meanwhile, Russia's state-owned RIA news agency quoted Deputy Foreign Minister Sergey Ryabkov as saying it was entirely possible that the U.S.-Russia talks could end abruptly after a single meeting.

"I can't rule out anything; this is an entirely possible scenario and the Americans... should have no illusions about this," Ryabkov was quoted as saying. Officials from the two countries held a working dinner Sunday night ahead of the more formal talks on Monday in Geneva.

"Naturally, we will not make any concessions under pressure and in the course of threats that are constantly being formed by the Western participants of the upcoming talks," Ryabkov said.

Blinken said, "I don't think we're going to see any [immediate] breakthrough" in the U.S.-Russia negotiations that continue along with other countries in Brussels and Vienna throughout the week.

But he said, "Ultimately this is up to President [Vladimir] Putin. It's his actions [with the Ukraine troop buildup] that are precipitating what he says he doesn't want," furthering conflict with the United States and its allies.

Blinken reiterated the U.S. threat to impose severe economic sanctions against Moscow in the event it invades Ukraine eight years after its 2014 annexation of Ukraine's Crimean Peninsula.

"Our strong preference is a diplomatic solution, but that's up to Russia," Blinken told ABC's "This Week" show. He said there is room for negotiations over military exercises in Europe and renewed arms limitations that he accused Russia of violating in the past.

The top U.S. diplomat, however, said Russia cannot violate other countries' borders or dictate whether NATO might accede to Ukraine's request for membership in the seven-decade-old Western military alliance. He said 60% of Ukrainians favor the country joining NATO.

Russia has denied it plans to invade Ukraine and has demanded an end to NATO expansion and a halt to the alliance's military exercises in central and eastern European countries that joined it after 1997.

The United States and NATO have said large parts of the Russian proposals are a non-starter.

Aside from Blinken's Sunday talk show interviews, a senior official in President Joe Biden's administration on Saturday anonymously laid out the U.S. stance on the talks with Russia.

"The main threats to European security over the past two decades have come from Russia and the forces with which it is aligned," the official said. "Russia has twice invaded and occupied its neighbors. It's interfered in a myriad of elections, including our own."

"It's used chemical weapons to conduct assassinations and violated foundational arms control treaties... So, any serious conversation with Russia about European security is going to have to address those issues...," the official said.

The official said the U.S. is not willing to restrict NATO's membership options.

"It is not up to Russia, for example, to decide for other countries who they can be allies with," the official said. "Those are decisions only for those countries and the alliance itself."

But the official said the U.S. was ready to talk about the possibility of each side restricting military exercises and missile deployments in the region.

After the Geneva talks, Russia is also due to hold negotiations with NATO in Brussels on Wednesday and at the Organization for Security and Cooperation in Europe in Vienna on Thursday.