Russia has complained to the United States about the detention of a Russian citizen in Liberia and his transfer to U.S. territory, Reuters cited Russian news agencies as saying today. Russian pilot Konstantin Yaroshenko was detained by U.S. special forces in a hotel in the Liberian capital Monrovia on May 28 and transferred to the United States, Interfax news agency quoted the man's lawyer, Alexander Bozhenko, as saying. The Russian Embassy in Washington sent a diplomatic note to the U.S. State Department saying it was unacceptable that Moscow had not received proper notification on the arrest, Russia's chief consul in New York Andrei Yushmanov was quoted as saying. "We also pointed out that the conditions in which our fellow citizen was kept were unacceptable and ran against all ethical rules and notions," Yushmanov told Interfax. A spokesman for Russia's embassy in Washington confirmed the note had been sent, RIA news agency said. Yaroshenko is facing drugs smuggling charges in New York, it said. The Russian Foreign Ministry was not immediately available for comment. Relations between Russia and the United States have warmed sharply in the past year after Moscow's war with U.S. ally Georgia in 2008 brought ties to a post-Cold War low. The arrest of 10 suspected Russian spies in the United States last month threatened to upset the "reset" in relations, but Washington agreed to quickly return them to Russia in return for four agents being released from Russian jails.