NUEVO LAREDO, Mexico - Mexico's government decided Tuesday to increase military control over security in the northeastern border state of Tamaulipas and purge corrupt police to counter a surge in drug cartel violence.
Clashes between cartel gunmen and troops as well as street gunfights among gang members have left more than 80 people dead in the state since April 5.
Authorities have blamed much of the recent violence on an internal power struggle within the Gulf cartel following the arrests of key leaders, but the gang has also been at war with the rival Zetas cartel in recent years.
Some 2,000 people protested against the violence in the Gulf of Mexico port city of Tampico on Sunday.
After a national security meeting in Reynosa, which borders the US state of Texas, Interior Minister Miguel Angel Osorio Chong announced a "new phase" to break up gangs, seal off drug trafficking routes and ensure residents can count on trustworthy police.
He said Tamaulipas will be divided into four security zones with a military officer in charge of each.
The authorities will widen the use of intelligence gathering to combat cartels and send more federal forces to cities, ports, airports, border crossings and roads.
Authorities will conduct reviews of the state and municipal police forces as well as the Tamaulipas prosecutor's office, to root out bad apples.
"We will not tolerate any public servant who has links with organised crime or who has committed acts of corruption," Osorio Chong said.
Ten state police officers have been detained in connection with an ambush that killed the region's chief of investigations on May 5, according to Mexican media.
The chief of bodyguards of Governor Egidio Torre Cantu is under investigation over the crime.
Osorio Chong insisted that the administration of President Enrique Pena Nieto had made progress against organised crime, detaining eight of the 12 most wanted men in Tamaulipas.
The violence in the state "can be explained in large part by the breakdown within these groups caused by the strong actions of the Mexican state," the minister said.
The resurgence of violence followed a relative lull in violence in Tamaulipas, a state that has witnessed some of the most gruesome drug-related crimes that have left 80,000 people dead in Mexico since 2006.
In another state plagued by drug cartel violence, Michoacan in the west, a mayor was arrested Tuesday on suspicion of links to organised crime.
The arrest of Jesus Cruz Valencia, mayor of the town of Aguililla, was the third of a mayor in Michoacan in the past two months. The state is a bastion of a cartel called the Knights Templar.
The state's number two official was arrested in April on charges of colluding with drug traffickers.