BOGOTA, Colombia -- Leftist rebels shot and killed a mayor and two town councilmen in southwestern Colombia after earlier telling them to resign or face execution, police said Saturday.

Luis Antonio Motta, mayor of Campoalegre, was driving with his nephew and the council members on Friday when they were stopped, forced from their car, and shot along a road outside the town.

Regional police commander Col. Luis Alejandro Gomez blamed their deaths on the Revolutionary Armed Forces of Colombia, or FARC.

Motta, 42, and the two councilmen -- Jorge Silva and Joaquin Perdomo -- were among hundreds of municipal leaders who were told beginning in June to either resign or face execution by the FARC -- the nation's largest rebel army waging a 38-year uprising against the state.

The government had assigned Motta two bodyguards, but they were not traveling with him Friday afternoon, Gomez said.

Threats against the nation's municipal leaders helped prompt the government of President Alvaro Uribe to declare a "state of unrest" in August allowing him to decree special measures to battle insurgents.

At least one other mayor and four council members have been killed since the threats began. About 150 mayors resigned following the ultimatums, but most have since returned.