MEXICO CITY – Four Mexican municipal police have been arrested on charges of aiding presumed drug cartel enforcers wounded in a clash this week with federal forces in the northern border city of Nuevo Laredo, the Attorney General’s Office said.

Armando Montoya, Moises Hernandez, Victor Manuel Alfaro and Luis Rene Alfaro were detained after a witness accused them of assisting four suspected hit men wounded in Wednesday’s clash with army soldiers, the AG office said in a statement.

According to authorities, the detainees helped the suspected criminals into their squad car and drove them away from the scene of the gun battle.

After receiving the witness’ testimony, army soldiers went to the municipal police headquarters in Nuevo Laredo, just across the border from Laredo, Texas, and discovered blood stains in the two patrol cars involved in the incident.

In addition to the four police, six other men also were arrested on charges of attacking the soldiers in the Concordia neighborhood of Nuevo Laredo.

Two unidentified individuals were killed in the clash.

Four assault rifles, a 9mm handgun, a grenade launcher, 13 grenades and five vehicles, four of them with Texas license plates, were seized from the six detained assailants.

The powerful and violent Gulf cartel, whose armed wing is a band of Mexican army veterans and deserters known as “Los Zetas,” is based in Tamaulipas state, where Nuevo Laredo is located.

Federal authorities acknowledge that organized criminal gangs, mainly drug cartels, have infiltrated municipal and state police forces and are seeking to purge their ranks of corrupt officers.

Drug-related violence has claimed nearly 15,000 lives in Mexico since December 2006, when newly inaugurated President Felipe Calderon began deploying tens of thousands of soldiers and federal police to fight the traffickers and their heavily armed enforcers. EFE