Confiscated weapons on display in Hermosillo, Mexico 

Mexican police have found a large arsenal of weapons thought to belong to drug traffickers at a house in the northern city of Hermosillo, after a nine-year old boy took a gun to school.

The boy's classmates saw the gun in his bag and reported it to the school authorities, who alerted the police, reports the BBC.

The weapon, which was reportedly loaded, was confiscated and police raided the boy's home.

There they found the weapons and thousands of rounds of ammunition.

The local authorities said they had found a powerful rifle (AR15) at the dining table and in one of the bedrooms, 13,000 rounds of ammunition, pistols and assault rifles, bulletproof vests and two money-counting machines.

Several high-calibre cartridges capable of penetrating body armour - so-called "cop-killers" - were also discovered.

In addition, the police confiscated military uniforms, portable radios and three vehicles, two of them armoured.

A police spokesman said a woman, thought to be the boy's mother, had been arrested at the house but that a man had managed to escape.

The boy was taken into the care of social workers.

This episode is further evidence of the damaging effects the country's violent drug war is having on young people, the BBC's Will Grant in Mexico reports.

Lobby groups have called on the authorities to do more to protect children from falling under the control of the powerful drug gangs, our correspondent says.

One local non-governmental organisation, he adds, has urged parents to routinely check their children's rucksacks for weapons, to help improve security in schools.