LONDONDERRY, Northern Ireland (AP) _ In another sign that peace is taking root, a former Irish Republican Army prisoner has been installed as the first mayor of a Northern Ireland city.

Cathal Crumley, 41, once sentenced to nine life terms for attempted murder and conspiracy to murder, was elected 21-8 by members of the Londonderry City Council after winning the backing of the main Catholic party, the moderate Social Democratic and Labor Party. Crumley is a member of the IRA-allied Sinn Fein party.

Dozens of supporters, including Martin McGuinness, Sinn Fein's education minister in the province's newly reinstated power-sharing government, cheered and applauded Monday night as Crumley accepted the office from outgoing mayor Pat Ramsey.

``I can assure you that during my term of office, no one will be denied their rights,'' said Crumley, whose convictions were overturned on appeal. ``I will be open, impartial, fair and pragmatic. The failed politics of exclusion end tonight.''

Crumley added that he hoped local Protestant politicians ``will have the maturity to react in reciprocal fashion for the betterment of this city.''

But Gregory Campbell, a council member from the hard-line Democratic Unionist Party, said Crumley's appointment does ``nothing to heal the divide or bridge the cavern.''

``It will make it wider and deeper than it has been before,'' he said.

Crumley was 18 when he was first jailed in 1976 for membership in the outlawed IRA.

He was released in 1982, but found guilty two years later on one count of attempted murder and eight counts of conspiracy to murder and a list of other terrorist offenses. The convictions were overturned two years later.