Pakistani interior minister Rehman Malik Sunday said he had formally asked Interpol to issue an arrest warrant for former military ruler Pervez Musharraf over the murder of ex-premier Benazir Bhutto.

"We have sent a request to the Interpol for the arrest of Pervez Musharraf," Malik told reporters in the capital Islamabad.

Bhutto was assassinated on December 27, 2007, while leaving an election rally in Rawalpindi, the headquarters of Pakistan's army.

Musharraf, who has lived in self-imposed exile in London and Dubai since August 2008, has indefinitely delayed plans to return home to contest elections after the government warned he would be arrested upon arrival.

Courts have issued warrants for his arrest over the 2006 death of Akbar Bugti, a Baluch rebel leader in the southwest Pakistan, and the 2007 assassination of Bhutto, whose widower is Pakistani President Asif Ali Zardari.

Malik, who was a close aide of Bhutto, has accused Musharraf of refusing to provide her with adequate security and of threatening her by telephone when she was in Washington before returning to Pakistan in October 2007.

Bhutto, who served two terms as prime minister, returned from exile two months before she was assassinated. Her widower, Asif Ali Zardari, led her Pakistan People's Party to election victory in 2008 and is now president.

At the time of Bhutto's death, Musharraf's government blamed the assassination on Pakistani Taliban chief Baitullah Mehsud, who denied any involvement and was subsequently killed in a US drone attack.