US Secretary of State Antony Blinken will fly Tuesday to Ukraine in a show of support amid fears of a Russian invasion, the State Department said.

Blinken, who will meet Wednesday in Kyiv with President Volodymyr Zelensky, will "reinforce the United States' commitment to Ukraine's sovereignty and territorial integrity," State Department spokesman Ned Price said.

Blinken will also head Thursday to Berlin for four-way talks with Britain, France and Germany on the Ukraine crisis.

The four transatlantic powers will discuss "joint efforts to deter further Russian aggression against Ukraine, including allies' and partners' readiness to impose massive consequences and severe economic costs on Russia," Price said in a statement.

Blinken's trip "follows extensive diplomacy with our European allies and partners about a united approach to address the threat Russia poses to Ukraine and our joint efforts to encourage it to choose diplomacy and de-escalation in the interests of security and stability," Price said.

It comes as Blinken's German and French counterparts also visit Ukraine, following travel to the frontlines by top EU diplomat Josep Borrell.

German Foreign Minister Annalena Baerbock on Tuesday was also holding talks in Moscow in hopes of defusing the crisis.

Russia last year sent tens of thousands of troops to the borders with Ukraine, according to Western officials who fear a new invasion.

Russia denies plans to invade but has demanded security guarantees from the West, including promises that NATO will not be expanded to Ukraine.

The United States and its allies last week held extensive talks with Russia, including in a meeting of the two countries' senior diplomats in Geneva.

Russia has publicly said that it is disappointed with the results, with Foreign Minister Sergei Lavrov saying Tuesday that Moscow needs answers before continuing dialogue.

The United States says that Russian demands are non-starters and that Ukraine, where thousands have died in a pro-Russian insurgency launched in 2014, has the right to make its own decisions.

European allies are cautious about admitting Ukraine to the alliance for fear of angering Russia.

The United States has warned of major economic consequences and has voiced hope that Germany would sever the soon-to-open Nord Stream 2 gas pipeline if Russia invades.