(Adds more details, context)
By Patricia Zengerle
WASHINGTON, July 6 (Reuters) - A forger sent a hoax letter to Russian media in an apparent bid to convince journalists that a senior U.S. lawmaker, Senator Richard Durbin, was trying to tell Ukrainian Prime Minister Arseny Yatsenyuk how to run his government, Durbin's office said on Monday.
The hoaxer wrote to Yatsenyuk on what appeared to be U.S. Senate letterhead, claiming to be Durbin, the number two Democrat in the Senate, a leading American voice on Ukraine-related issues who traveled to Kiev in May to discuss Russian aggression.
Ben Marter, a spokesman for Durbin, said his office had told the CIA and the FBI about the letter. Marter said he first learned about it when he was contacted by Russian state-owned media asking for comment.
The forged letter was on paper that resembled U.S. Senate stationery, but with Durbin's title wrong. The Illinois lawmaker is assistant Democratic leader, but the forged letter called him "Assistant Minority Leader."
It suggested that Yatsenyuk "invest every effort" to keep some officials in place, including the agriculture minister and the head of the country's nuclear monopoly. But it said the U.S. Senate feels some others do not have the qualities necessary for their jobs.
"Senator Durbin has been outspoken in his criticism of Russia's invasion of Ukraine and supportive of Ukrainian efforts to reform their economy and defend their nation. This letter is a forgery and was obviously written by somebody with a tenuous grasp of the English language," Marter said.
Drawing censure from Moscow, some members of Congress have been pushing President Barack Obama for a tougher response after Russia's annexation of Crimea and reports of Russian tanks and artillery crossing into Ukraine.
Last month, both Democrats and Republicans in Congress backed legislation that would authorize $300 million for Ukrainian security assistance, but specifies that half the money would be withheld unless at least 20 percent of it is spent on lethal aid for the Kiev government. (Reporting by Patricia Zengerle; Editing by Grant McCool)