Police chief steps down in Mexico

The police chief of a northern Mexican city has resigned following a wave of violence involving drug traffickers, officials say.

Guillermo Prieto was one of 22 police officers in Ciudad Juarez named on a hit list of drug gangs.

Seven of those named have been killed in recent weeks, and most of the others are said to have resigned.

President Felipe Calderon has deployed more than 30,000 troops across Mexico to stem drug-related violence.

Some government spokesmen have argued that the latest wave of killings is a sign the cartels are being weakened by the massive troop deployment and that they are trying to hit back.

But others say they are still a dangerous force that can adapt to anything, in order to maintain control of a drugs supply to the United States that is said to be worth around $20bn (£10bn).

More than 1,000 people have died so far this year in cartel-related violence.