Afghanistan’s controversial intelligence chief was wounded in an assassination attempt in Kabul on Thursday.

Afghanistan's controversial intelligence chief was wounded in an assassination attempt in Kabul on Thursday, officials said.

Asadullah Khalid, who heads the National Directorate of Security, was injured in a grenade attack in a spy agency guesthouse, police said.

A former cabinet minister and a key anti-Taliban figure, he was nominated to head the NDS by President Hamid Karzai in August and approved by parliament despite objections from Western rights groups and accusations that he tortured detainees.

There were few details on the nature of the attack. Witnesses heard an explosion. Police said Khalid was wounded by a grenade, but unconfirmed reports by senior government officials said it had been a suicide attack.

A security source told AFP that Khalid had been rushed to hospital and given major blood transfusions. A Western diplomat told AFP that Khalid was "seriously wounded".

There wasn’t any immediate claim of responsibility but Taliban insurgents waging a war to topple the government will be suspected of being behind the assassination attempt.

Khalid is fiercely anti-Taliban and close to the Karzai family.

His appointment was interpreted as part of an effort by the president to secure his power base before anointing a successor to stand for election in 2014.