"One of the big issues is Allen West's verbal explosions, where he continually says extremely divisive things, " said Eric Johnson, Murphy's campaign consultant.

CNN: West faces fight from all sides in new district

Election candidates announced so far are: Craig Clarke (Independent), Tim Collins (Independent), George Ferguson (Independent), Geoff Gollop (Conservative), Neil Maggs (Respect), Spud Murphy (Independent), Eric Mutch (Independent), Daniella Radice (Green), Marvin Rees (Labour), Jon Rogers (Liberal Democrat) and Andy Thorne (Independent).

BBC: George Ferguson

Associated Press writers Bridget Murphy and Bob Salsberg in Boston, Lynn Berry in Moscow, and Kimberly Dozier, Adam Goldman, Eric Tucker, Matt Apuzzo, and Eileen Sullivan in Washington contributed to this report.

NPR: Boston Bomb Investigation Extends To Russia