U.S. police nab guns bound for Mexico

By Tim Gaynor

PHOENIX (Reuters) - U.S. border police have arrested four men and seized three shipments of guns, ammunition and weapons parts bound for Mexico, authorities said on Wednesday, weapons that would likely have been used by warring drug cartels.

U.S. and Mexican authorities are working closely to curb the illegal trade in arms to Mexico, where more than 7,000 people have been murdered by the cartels since the start of last year.

The Department of Homeland Security said border police in Arizona seized 10 guns and thousands of rounds of ammunition hidden in a pickup truck bound for Mexico on Saturday, and arrested two men, a Mexican and a U.S. citizen.

In two separate operations in south Texas last week, border police seized guns, bullets, rifle barrels, firearm accessories and gun powder from vehicles headed to Mexico, and arrested a U.S. citizen and a Mexican national, the DHS said in a news release.

Gun sales are heavily restricted in Mexico. Investigators say nine out of 10 guns retrieved from crime scenes south of the border are traced back to U.S. gun dealers.

On Monday, a Phoenix gun dealer went on trial on charges he sold hundreds of weapons, including AK-47 assault rifles, to smugglers knowing they would send them to a powerful cartel in Sinaloa state on Mexico's Pacific coast.

Mexican cartels pose a clear threat to U.S. national security, Vice President Joe Biden said on Wednesday as he named a drug czar to lead the U.S. fight against narco-trafficking.

"Violent drug trafficking organizations threaten both the United States and Mexican communities," Biden said at a ceremony to nominate Seattle police chief Gil Kerlikowske as the country's new drug czar.

U.S. Senate lawmakers are to hold two hearings in coming weeks to assess the ability of U.S. security forces to handle the rise in crime on the U.S. side of the border related to Mexican traffickers.

(Editing by Philip Barbara)