UPDATE 2-U.N. Security Council to convene on Friday at Russia's request -diplomats

(Adds U.S. comment)

By Humeyra Pamuk

WASHINGTON, March 10 (Reuters) - The United Nations Security Council will convene on Friday at Russia's request, diplomats said, to discuss Moscow's claims, presented without evidence, of U.S. "biological activities" in Ukraine, a move Washington described as gaslighting.

The meeting is expected to be in the morning.

"Russian Mission asked for a meeting of #SecurityCouncil for 11 March to discuss the military biological activities of the US on the territory of #Ukraine," Dmitry Polyanskiy, First Deputy Permanent Representative of Russia to the United Nations said in a tweet.

The United States on Wednesday denied renewed Russian accusations that Washington was operating biological warfare labs in Ukraine, calling the claims "laughable" and suggesting Moscow may be laying the groundwork to use a chemical or biological weapon.

"This is exactly the kind of false flag effort we have warned Russia might initiate to justify a biological or chemical weapons attack," Olivia Dalton, spokesperson, U.S. Mission to the United Nations said on Thursday.

"Russia has a well-documented history of using chemical weapons and has long maintained a biological weapons program in violation of international law...We’re not going to let Russia get away with gaslighting," she added.

Late on Tuesday, Russia repeated its accusation of several years that the United States is working with Ukrainian laboratories to develop biological weapons. Such assertions in Russian media increased in the run-up to Moscow's military move into Ukraine and were made as recently as Wednesday by foreign ministry spokesperson Maria Zakharova.

In a statement, also released on Wednesday, State Department spokesman Ned Price said Russia "is inventing false pretexts in an attempt to justify its own horrific actions in Ukraine."

Like many other countries, Ukraine has public health laboratories researching how to mitigate the threats of dangerous diseases affecting both animals and humans. Its laboratories have received support from the United States, European Union and World Health Organization. (Reporting by Humeyra Pamuk; Writing by Eric Beech; editing by Diane Craft and Lincoln Feast.)