(Adds Rosneft share price fall, changes dateline)
MOSCOW/LONDON, April 28 (Reuters) - The United States added Igor Sechin, the head of Russian state-controlled energy company Rosneft, to its Ukraine-related sanctions list on Monday.
Sechin, who was included on the list posted on the U.S. Treasury Department's website, is a powerful ally of Russian President Vladimir Putin and is the most senior energy executive to be targeted by U.S. sanctions so far.
The sanctions did not name Rosneft itself but shares in the company fell after the announcement. At 1455 GMT, Rosneft's shares were down 1.9 percent on the Moscow stock exchange, compared with a 0.9 percent rise in the Micex index.
Shares in British oil major BP traded down 1.5 percent following the U.S. government's decision. BP holds a 19.75 percent stake in Rosneft.
Seven Russian officials and 17 companies were included in the latest list of sanctions over the Ukraine crisis.
Rosneft jumped to the top of the global production league last year with its $55 billion acquisition of rival TNK-BP.
Full list of sanctions here: here (Reporting by David Sheppard, editing by Mark Potter and Nigel Stephenson)