MOSCOW, April 16 (AFP) - Foreign ministry spokeswoman Maria Zakharova said on Thursday (Apr 15) that a Russian response to new US sanctions was "inevitable" and that the ministry had summoned US ambassador to Moscow John Sullivan.

The United States earlier on Thursday announced economic sanctions against Russia and the expulsion of 10 diplomats in retaliation for alleged election interference, a massive cyber attack and other hostile activity.

"The United States is not ready to come to terms with the objective reality that there is a multipolar world that excludes American hegemony," Zakharova said in televised remarks.

"We have repeatedly warned the United States about the consequences of its hostile steps, which dangerously increase the degree of confrontation between our countries."

"A response to sanctions is inevitable," she added.

Zakharova also said that Russia's foreign ministry had summoned US ambassador Sullivan for a conversation that she said "will be difficult for the American side".

The sanctions come after tensions soared in recent weeks, with Russia massing troops on its border with Ukraine and Kiev's Western allies calling on Moscow to back down.

Ties had already plunged last month when US President Joe Biden agreed with a description of Russian President Vladimir Putin as a "killer".

"Washington must realise that it will have to pay for the degradation of bilateral relations," Zakharova said on Thursday.

"The responsibility for what is happening lies entirely with the United States."

Relations have been in free fall since 2014, when Russia annexed Crimea from Ukraine and fighting erupted between Kiev's forces and pro-Russia separatists in the east.

The United States has in the years since slapped Russia with a series of sanctions including over the alleged hacking of its 2016 presidential elections and the recent jailing of Kremlin critic Alexei Navalny.