Updated

GUADALAJARA, Mexico -- Unidentified gunmen ambushed a convoy of five police vehicles in the western Mexico state of Jalisco on Thursday, killing nine officers and leaving one missing.

The 20 officers in the convoy were outnumbered by the attackers, who were riding in about ten sport utility vehicles, the Jalisco state public safety department said in a statement.

The ten officers who survived the attack fought an hours-long battle with the gunmen, and several were wounded.

The attackers used grenades and assault rifles before fleeing into neighboring Michoacan state.

Michoacan is home to the violent La Familia cartel, which has been known to launch fierce attacks on police convoys.

Jalisco authorities complained that Michoacan officials had not joined in the search for the attackers.

And in Zapopan, a suburb of the Jalisco state capital of Guadalajara, two 2-year-old boys and three other people were wounded by grenade fragments during an attack on a private home.

The Zapopan municipal police department said the toddlers, a 17-year-old girl and two adults were all were bystanders on a street outside the home, and said none of the wounds appeared life threatening.

Witnesses said men in a pickup fled after two explosions were heard. The attack appeared directed at a house located about a block from the local church.

Mexico's drug gangs frequently use grenades in such attacks, and several high-level drug traffickers have been known to reside in the upscale suburb of Guadalajara, Mexico's second-largest city.

Also Thursday, the United States delivered three mobile X-ray inspection vehicles to Mexico as part of the Merida Initiative anti-drug aid plan.

Mexico's tax agency said the vehicles will be used to inspect freight and merchandise shipments to detect irregularities.

The United States will deliver 10 more of the vehicles, worth $1 million apiece, over the next two months as part of the multiyear, $1.4 billion Merida Initiative that the U.S. Congress approved to aid Mexico and other countries fight the drug war.