Russia lodges protest with US over senator's call to 'take out' Putin

Russia's foreign ministry summoned US ambassador in Moscow on Saturday to lodge protest over remarks by US Senator Lindsey Graham advocating that President Vladimir Putin be assassinated.

It said in a statement that failure to unambiguously condemn the remarks and take concrete measures "will have a further devastating effect on Russian-American relations", already in tatters following Western sanctions against Russia over its invasion of Ukraine.

US Ambassador John Sullivan was summoned to the ministry to be told that Graham's comment would be treated as a serious crime in Russia.

"This is a public, terrorist appeal that is completely unacceptable," the ministry said.

Graham, a Republican from South Carolina, called on Twitter for someone in Russia to "take this guy out" - referring to Putin.

White House spokesperson Jen Psaki told reporters on Friday: "We are not advocating for killing the leader of a foreign country or regime change. That is not the policy of the United States."