The Mexican military has arrested 35 police officers suspected of having ties to the Zetas drug cartel, one of the country’s most powerful and violent criminal organizations.

The officers were arrested in operations carried out by the Mexican Naval Infantry, or Marines, Saturday in the eastern states of Veracruz and San Luis Potosi.

“They were all police officers in the Veracruz public security department and allegedly collaborated with the Zetas criminal organization," the Navy said in a statement, the BBC reported.

The Zetas, formed from a group of former Mexican Army special forces that originally served as enforcers for the Gulf cartel before becoming independent, have been active in Veracruz, a key transit point for drug trafficking into the U.S., and have been engaged in a brutal turf war with rival cartels.

Since last year, thousands of federal officers and members of the armed forces have been deployed in Veracruz.

The navy has taken over anti-narcotics duties from police in several municipalities in Veracruz over concerns of corruption as many police officers are on cartel payrolls.