BOSTON (AP) -- U.S. Rep. Michael Capuano has decided not to run for U.S. Sen. John Kerry's seat if Kerry is confirmed as secretary of state.

The Somerville Democrat has been weighing a run, but released a statement Tuesday saying after careful consideration he's decided not to enter the race and "looks forward to focusing on the important issues facing the new Congress."

Capuano's exit further narrows the list of possible Democratic candidates.

So far, Congressman Ed Markey is the only announced Democratic hopeful.

Rep. Stephen Lynch is also considering a run and plans to decide soon whether to get into the race.

Former U.S. Sen. Scott Brown is weighing a run on the Republican side.

Kerry has already signaled his support for Markey, as has Victoria Kennedy, the widow of the late U.S. Sen. Edward Kennedy.

Berkshires state Sen. Benjamin Downing last week decided against running for Kerry's seat.