Chavez resigns as the government continues to try and contain nationwide drug violence [Reuters]

Mexican attorney-general Arturo Chavez has resigned from his key post in the fight against drug trafficking after just 18 months in office.

President Felipe Calderon accepted the resignation on Thursday and nominated 41-year-old lawyer Marisela Morales to take over, the first woman to hold the post if she is approved.

The departure came three weeks after the release of a 2009 US diplomatic cable by whistle-blowing website WikiLeaks in which US embassy officials found Chavez's appointment to be "totally unexpected and politically inexplicable".

"I have to withdraw from this important position to deal with strictly personal and urgent issues," said Chavez 18 months after he took the job amid widespread scepticism for his weak image in a country fighting a drug war.

Al Jazeera's Mariana Sanchez, reporting from Mexico City, said the attorney-general's resignation comes at a time when there has been increasing criticism over the war on drugs.

Calderon lauded Chavez's role in a crackdown on organised crime launched at the start of his presidential term in late 2006.
But rights groups had criticised the appointment for Chavez's apparent inaction over the killings of dozens of women in Ciudad Juarez when he was attorney general of northern Chihuahua state in the 1990s.

Spiralling violence
Chavez was the second attorney-general under Calderon to resign, following the departure of Eduardo Medina Mora, who is now ambassador to Britain.

His departure comes at a time of spiralling violence in the drug war, which has claimed some 35,000 lives since it was launched, according to official figures.

In nominating Marisela Morales, Calderon said the current head of the organised crime special investigations unit "enjoys prestige inside and outside the country".

As head of the organised crime unit, Morales made more public appearances in the capture of major drug lords than her boss.

Source: Al Jazeera and agencies