Gunmen in the drug-violence-riddled Mexican border city of Ciudad Juarez fired into a crowd of parents outside a school, killing one person and wounding at least four others.

Witnesses said the gunmen arrived in two unmarked cars and were chasing a man, who ran for cover into the crowd outside the school.

The man they were chasing was killed, and three women and one other man were seriously wounded in the gunfire.

None of the children in the school were injured.

Authorities say they are investigating the incident to see whether it is related to the gangs involved in drug trafficking.

Mexican authorities say at least 40,000 people have died since President Felipe Calderon's army began cracking down on drug cartels in 2006.