U.S. and Russian negotiators face off in Geneva over Ukraine

National flags of Russia and the U.S.

GENEVA, Jan 10 (Reuters) - After days of pessimistic statements on both sides, the United States and Russia began tough negotiations in Geneva on Monday that Washington hopes can avert the danger of a new Russian invasion of Ukraine without conceding to the Kremlin's far-reaching security demands.

The talks between Russian Deputy Foreign Minister Sergei Ryabkov and Deputy U.S. Secretary of State Wendy Sherman began at the U.S. diplomatic mission in Geneva with U.S.-Russia relations at their most tense since the Cold War ended three decades ago.

The pair made only brief eye contact when they posed for photographs beforehand.

"The talks promise to be long and substantial," the Russian diplomatic mission in Geneva tweeted, with a picture of the two lead negotiators standing in front of their national flags.

Sherman said "the U.S. will listen to Russia's concerns and share our own" in an earlier tweet from Geneva, adding that no discussions on European security would be held without the presence of other allies. Discussions will move to meetings in Brussels and Vienna later this week.

Nearly 100,000 Russian troops are gathered within reach of the border with Ukraine in preparation for what Washington and Kyiv say could be a new invasion, eight years after Russia seized the Crimea peninsula from the former Soviet republic.

Russia denies invasion plans and said it is responding to what it calls aggressive behavior from the NATO military alliance and Ukraine, which has tilted toward the West and aspires to join NATO.

Last month, Russia presented sweeping demands including a ban on further NATO expansion and an end to the alliance's activity in central and eastern European countries that joined it after 1997.

The United States and NATO say large parts of the Russian proposals are non-starters.

'WE NEED GUARANTEES'

Ryabkov told RIA news agency Russia would not accept U.S. attempts to limit the agenda to discussion of military exercises and missile deployments - the topics outlined by the Biden administration as areas it is willing to broach.

"We need legal guarantees of the non-expansion of NATO and the elimination of everything that the alliance has created since 1997," Ryabkov said.

Russia had tried to show flexibility for the past 30 years and it was time for the other side to be flexible, he said. "If they are unable to do this, they will face a worsening situation in their own security."

The two countries are also at odds over Russia's deployment of troops in Kazakhstan after an uprising there last week, its support for Belarus in a migrant crisis on the EU's border, and what Washington sees as Russia's use of its gas supplies to Europe to gain political leverage over its neighbours. 

NATO Secretary General Jens Stoltenberg, who will meet the Russian team on Wednesday in Brussels, said Russia and the West could find a pathway to avoid conflict.

"What we are hoping for is that we can agree on a way forward, that we can agree on a series of meetings, that we can agree on a process," Stoltenberg said.

Ukraine's Deputy Prime Minister Olga Stefanishyna, appearing alongside him, said Russia should not set conditions while its tanks remained near the Ukrainian border.

'UKRAINE MUST BE PRESENT'

On the streets of Kyiv, residents questioned why their country was not at the table. 

"I think it should not be this way," said a 59-year-old man who gave his name as Oleh. "Ukraine must be present during those meetings because it is a more interested party than other countries... Ukraine must be sitting in the first row."

Russia has scorned Ukrainian President Volodymr Zelenskiy as a viable negotiating partner, but the United States and other western governments have said they are fully committed to Ukraine's sovereignty and territorial integrity.

As Ukraine is not a NATO member, it could not count on alliance members to defend it. But U.S. President Joe Biden has repeatedly warned Russian President Vladimir Putin that the United States and European allies would impose tough sanctions if Russia chose to invade Ukraine. Putin has said new sanctions could lead to a "complete breakdown in ties."