Twenty killed in Mexico violence

Police killed 15 gunmen in a fierce battle just south of the Arizona border after tracking assailants believed to have abducted and killed five Mexican policemen into the nearby hills with a helicopter.

Sonora state police say about 40 assailants drove into the town of Cananea, 20 miles south of the US border, in up to 15 vehicles and seized four policemen in two patrol cars.