Five killed in attacks on Mexico police

MEXICO CITY: Four police officers and a doctor died in three separate attacks on Mexican police overnight near the northern city of Monterrey, amid a wave of drug violence in the area, authorities said Thursday.

Unidentified assailants threw a grenade and fired at a police station in the town of Valle Verde, killing two officers and a doctor who was in the building, said Jorge Domene, security spokesman for Nuevo Leon state, which borders the United States.

A female police officer was killed in an attack on her patrol car in the nearby town of Guadalupe and another police officer was shot dead at a road junction, Domene told a news conference.

Police were investigating whether the killings were linked to drug gangs, and were on alert for new attacks, he added.

Nuevo Leon and the neighboring state of Tamaulipas have seen some of Mexico's worst drug violence in recent months, blamed on turf battles between the Gulf gang and its former allies the Zetas.

More than 30,000 people have been killed in drug-related violence since December 2006, when President Felipe Calderon ordered a military crackdown on the country's powerful drug cartels.