Mexico is sending 3,300 soldiers and federal police to fight drug gangs in the border city of Tijuana, which has become a major smuggling route for cocaine and methamphetamine entering the United States.

The offensive expands a crackdown on organized crime by President Felipe Calderon, who sent 7,000 troops to his home state of Michoacan immediately after taking office on December 1.

"We will carry out all the necessary actions to retake every region of national territory," Mexican Interior Secretary Francisco Ramirez Acuna said in a news conference Tuesday. "We will not allow any state to be a hostage of drug traffickers or organized crime."

The Tijuana force consists of 2,620 soldiers, 162 marines and 510 federal police, and will be backed by 28 boats, 21 planes and nine helicopters, Ramirez Acuna said.

The force will hunt down suspected traffickers, patrol the coast and man checkpoints in a city that lies across the border from San Diego and is one of the world's busiest border crossings. It is a transshipment point for cocaine heading north from Colombia, as well as locally produced methamphetamine and marijuana.

Several hundred body armor-clad federal police were seen driving in convoys into the city on Tuesday. The rest of the force was expected to arrive in the coming days.

Tijuana has been plagued by fighting between rival drug gangs. Last year, there were more than 300 killings in the city. In one of the most gruesome crimes, assailants in June abducted three policemen and a civilian in the nearby town of Rosarito, killing them and dumping their severed heads on a Tijuana beach.

Tijuana Mayor Jorge Hank Rhon welcomed the soldiers, saying he would like them to work hand- in-hand with city police who are establishing random security checkpoints.

"I hope this will make Tijuana a safer place," he said.

However, he said the deployment did not mean the city was being militarized.

Calderon was elected on a law-and-order platform.

Last month, he sent 7,000 soldiers and federal police to the western state of Michoacan, which has been plagued by execution-style killings and beheadings as rival drug gangs fight over marijuana plantations and smuggling routes.

The troops have arrested more than 50 people, including several suspected leaders of the feuding cartels, and seized large quantities of gold, bulletproof vests, military equipment and shirts with federal and municipal police logos.

Calderon is scheduled to make his first visit to the troops on Wednesday at a military base.

"The operations will allow us to re-establish the minimal security conditions in different points of Mexico so we can recover little by little our streets, our parks and our schools," Calderon said in a New Year's message on Tuesday.

Calderon's predecessor, Vicente Fox, promised the "mother of all battles" against organized crime, sending in thousands of soldiers and federal police to some drug-embattled towns and arresting several major drug kingpins.

But the arrests appeared to spark more violence as gangsters battled to take over the smuggling routes of those killed or arrested.