BUCHAREST (Reuters) - The United States will ask the U.N. General Assembly to suspend Russia from the Human Rights Council, the U.S. ambassador to the United Nations said on Monday, after Ukraine accused Russian troops of killing dozens of civilians in the town of Bucha.

A two-thirds majority vote by the 193-member assembly in New York can suspend a state from the council for persistently committing gross and systematic violations of human rights.

Speaking in Bucharest on Monday, Ambassador Linda Thomas-Greenfield said: "Russia's participation on the Human Rights Council is a farce.

"And it is wrong, which is why we believe it is time the UN General Assembly vote to remove them."

Thomas-Greenfield told Reuters she aimed to put the move to suspend Russia to a vote in the General Assembly this week.

Since the Ukraine invasion began on February 24, the Assembly has adopted two resolutions denouncing Russia with at least 140 yes votes. Moscow says it is carrying out a "special military operation" to destroy Ukraine's military infrastructure.

"My message to those 140 countries who have courageously stood together is: the images out of Bucha and devastation across Ukraine require us to now match our words with action," Thomas-Greenfield, visiting Romania to see how it is coping with an influx of Ukraine refugees, told reporters.

Russia is in its second year of a three-year term on the 47-member Geneva-based council. Moscow's mission to the United Nations in New York did not immediately respond to a request for comment.

The council cannot make legally binding decisions but its decisions send important political messages and it can authorise investigations.

It last month set up an investigation into alleged rights violations, including possible war crimes, in Ukraine since Russia's invasion. Thirty-two members voted in favour of the resolution, brought by Ukraine. Russia and Eritrea voted against while 13, including China, abstained.

Bucha's deputy mayor said around 50 bodies found after Kremlin forces withdrew were the victims of extra-judicial killings carried out by Russian troops.

Reuters could not independently verify that information.

Ukrainian authorities said they were investigating possible war crimes there. The Kremlin categorically denied any accusations related to the murder of civilians in the town.

The United States has said war crimes have been committed in Ukraine and U.S. experts were gathering evidence to prove it.

The General Assembly has previously suspended a country from the Human Rights Council. In March 2011, it unanimously suspended Libya because of violence against protesters by forces loyal to then leader Muammar Gaddafi.

(Reporting by Michelle Nichols, editing by John Stonestreet)