MILWAUKEE (Reuters) - Milwaukee Mayor Tom Barrett announced on Friday his candidacy for the Democratic nomination to challenge Wisconsin Republican Governor Scott Walker in a recall election, setting up a possible rematch of the 2010 election.

Barrett's entrance into the race was expected and came just hours after a state agency certified the recall election against Walker, whose support for controversial restrictions to some public sector unions in Wisconsin sparked the recall bid.

Barrett said he did not make the decision lightly.

"Wisconsin needs a governor who is focused on jobs, not ideology; a leader committed to bringing our state together and healing political wounds, not pitting people against each other and catering to the special interests," he said in a statement.

Ciara Matthews, communications director of Walker's campaign committee, said in a statement that Barrett's "record of failed leadership as mayor of Milwaukee has twice been rejected by Wisconsin voters."

(Reporting by Brendan O'Brien; Writing by David Bailey; Editing by Greg McCune)