KITTERY – Mark Lawrence, a former state Senate president now serving as York County district attorney, announced Wednesday he has filed papers to run for the congressional seat being vacated by fellow Democrat Tom Allen.

Lawrence became the third Democrat from the 1st District to file with the Federal Election Commission, joining Michael Brennan and Chellie Pingree. At least two other Democrats and several Republicans are also weighing bids.

Lawrence was the Democratic nominee for the U.S. Senate in 2000, losing to Republican incumbent Olympia Snowe.

A Kittery native, Lawrence made the announcement outside the Portsmouth Naval Shipyard, where his father worked for 40 years.