Gunmen attack Mexican marines at 3 spots in border city; officials report 13 attackers killed

Officials in northern Mexico say at least 13 people have been killed in three separate clashes between Mexican marines and gunmen in the border city of Matamoros.

Matamoros is across the border from Brownsville, Texas, and is in an area that is being fought over by the rival Gulf and Zetas drug cartels.

The government of Tamaulipas state says the three gunbattles occurred Sunday afternoon when gunmen attacked troops in different parts of Matamoros. Its statement describes the attackers only as "armed civilians" and doesn't say if the gunmen are suspected of belonging to cartels.

Officials say one woman was among the 13 dead civilians. No marine casualties have been reported.