Pakistan on Friday appointed a new head of its powerful military intelligence agency -- an organisation which has been accused of maintaining links with Taliban militants in the past.

"Prime Minister Yousuf Raza Gilani has appointed lieutenant general Zaheer ul Islam, corps commander Karachi, as new director general Inter Services Intelligence (ISI)," a senior government official told AFP.

A statement later issued by Gilani's office confirmed the new appointment but gave no details.

"The outgoing ISI chief lieutenant general Ahmed Shuja Pasha is retiring on March 18 and Islam will take up the position then," the official said.

Pasha, who was appointed ISI chief in September 2008, is considered to be close to Pakistan's military chief Ashfaq Kayani, who ran the intelligence agency himself until October 2007.

The ISI is feared within Pakistan as it plays a central, although covert, political role in a country that has spent more than half of its history since independence in 1947 under military rule.

Tensions between the army and government soared last year over a note seeking Washington's help to curb the military's powers amid fears of a coup after the US raid that killed Osama bin Laden in the city of Abbottabad.

The memo allegedly delivered to the then chairman of the US Joint Chiefs of Staff, Admiral Mike Mullen, was first made public by an American-Pakistani businessman in October.

Both Pasha and Kayani wanted a judicial inquiry into the affair, dubbed "memogate", while the civilian government sought to play it down. A judicial commission appointed by the Supreme Court is investigating.

The ISI has helped capture or kill hundreds of senior Al-Qaeda militants in Pakistan since it joined the "war on terror" in 2001, including Khalid Sheikh Mohammed, the self-confessed 9/11 mastermind.

But many Western officials suspect that, having helped to create the Taliban that ruled Afghanistan from 1996 to 2001, the organisation has been playing a double game.

Pakistan strongly denies any such links, although former military ruler Pervez Musharraf admitted in 2006 that some retired Pakistani intelligence officers may have been abetting extremists.