MEXICO CITY, MEXICO - Drug traffickers killed seven Mexican policemen on Tuesday, the latest slayings in a wave of police murders as the army wages a battle against cartels.

Police searching a drug hide-out in Culiacan in the Pacific state of Sinaloa were shot at from inside the building by the traffickers, who also threw a grenade, the government said.

Seven police officers were killed and four were injured. Violent Sinaloa state is the cradle of Mexico's drug trade and home to the country's most wanted man, drug kingpin Joaquin "Shorty" Guzman.

"We have to increase the firepower of police and improve the bulletproofing of their vehicles," Public Security Minister Genaro Garcia told Mexican radio.

Earlier this month President Felipe Calderon deployed some 2,700 police and soldiers to Sinaloa as part of an assault on the country's most powerful traffickers.

But the effort has failed to curb the killings. Some 1,400 people have died in drug-related violence this year, up around 50 percent from this time in 2007. --REUTERS