Mexican gunmen kill four policemen

MEXICO CITY, May 17 (UPI) -- Gunmen killed four police officers in northern Mexico in the latest bout of drug-related violence to plague the country.

Mexican authorities said a group of about 40 men entered the town of Cananea on the U.S.-Mexican border and kidnapped and killed the officers, El Universal newspaper reported Thursday.

Police said they managed to track and kill some of the gunmen hours after the shooting.

Drug-related attacks on police and Mexican citizens have been on the rise in recent months, prompting President Felipe Calderon to deploy about 20,000 troops to states where drug cartels are known to operate.