Washington (CNN) - Dan Coats has a sense of humor.
The Republican Senator from Indiana is jokingly blaming Russia for his showing up and questioning of a witness at the wrong subcommittee hearing.
"I think the Russians have been messing with my schedule," Coats said on Twitter, kidding about a possible conspiracy from Moscow.
Coats was one of a handful of U.S. lawmakers singled out by Russia in counter sanctions last month following initial sanctions by Washington and European allies over Moscow's annexation of neighboring Ukraine's autonomous Crimean peninsula.
Coats' tweet was referring to his mistake earlier Thursday, when the Appropriations member appeared at the wrong subcommittee hearing. During a lengthy introduction to a question, he began to commend a witness for his department's quick response to a letter Coats had sent.
After an aide slipped him a piece of paper, Coats interrupted himself, saying "I just got a note saying I'm at the wrong hearing."
The witness, David Cohen, the undersecretary of treasury for terrorism and financial intelligence, responded, saying "Well, that would explain why I didn't know anything about this letter."
Coats went on to say that "this is the first time this has ever happened to me," adding that "I saw some familiar faces and I thought this is where I should be," and "I'll go try to find out where I'm supposed to be."
Coats served two terms in the Senate in the late 1980's and 1990's. Later he served as U.S. ambassador to Germany before winning election back to the Senate in 2010.
The mishap was first reported by the Washington Post.
CNN Political Editor Paul Steinhauser contributed to this report