With Boston mayor Thomas Menino retiring after five terms, there will be an open race for the post for the first time in two decades. But Rep. Stephen Lynch (D) -- the underdog in the primary for Massachusetts's open Senate seat -- has made clear that he isn't interested.

Rep. Stephen Lynch (Charles Krupa/AP)

“Many people have asked me over the past two days whether I would consider running for Mayor of Boston," Lynch said in a brief, blunt statement. "While I thank them for their encouraging words, I want to be clear: I am not interested in running for Mayor. I am not interested in serving as Mayor. I will not be a candidate for Mayor. I am running for the United States Senate. Thank you.”

Lynch faces Rep. Ed Markey in an April 30 primary for the seat vacated by Secretary of State John Kerry (D). Markey has the support of the Democratic establishment and leads in polls, although the more conservative Lynch could do well with unaffiliated voters.