Top U.S. and Russian officials held crucial talks Monday with tensions soaring over Ukraine and security demands from Moscow, but there was little hope of a diplomatic breakthrough. 

U.S. Deputy Secretary of State Wendy Sherman and Russian Deputy Foreign Minister Sergei Ryabkov opened their meeting at the U.S. mission in Geneva at 8:55 a.m. (0755 GMT). 

"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.

State news agency RIA Novosti on Monday quoted Ryabkov as saying he feared Washington was not taking seriously Moscow's demand of an end to NATO's eastward expansion.

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. 

The meeting kicked off with low expectations as Rybakov on Sunday said Russia will not give in to U.S. pressure or make any concessions ahead of the strategic stability talks, while U.S. Secretary of State Antony Blinken also said that he does not expect breakthroughs in U.S.-Russia security talks.

Discussions will move to meetings in Brussels and Vienna later this week.

(With input from agencies)