A senior police official probing the suicide attack on former Pakistan premier Benazir Bhutto's [Images] convoy in Karachi has been removed in the wake of objections raised by her Pakistan People's Party.

DIG (Investigation) Manzoor Mughal, who was heading the probe, has applied for leave and will no longer be handling the probe, Interior Ministry spokesman Javed Iqbal Cheema said.

Bhutto and the PPP had been demanding Mughal's removal alleging he was present when the former premier's husband Asif Ali Zardari was tortured in police custody in 1999 after being arrested on graft charges.

Cheema also said the probe into the blasts was proceeding in the right direction and several clues had been uncovered by investigators. He did not give details.

The PPP, however, was not placated by the government's move and threatened it would approach the courts if the government did not order an "independent and impartial" investigation and rope in foreign experts.

"We will move the court of law if the government does not order an inquiry by an independent investigator. Bhutto's demand for bringing in foreign experts is also pertinent as this investigation will show who is behind this attack," said Bhutto's lawyer and aide Farooq Naik.

Naik also reiterated the PPP's demand for Bhutto's name to be removed from the Exit Control List which bars her from traveling abroad.

The government has already rejected Bhutto's demand for bringing in foreign experts, with Interior Minister Aftab Ahmed Khan Sherpao saying Pakistani investigators have the expertise to probe suicide attacks.

Chaudhry Shujaat Hussain, the chief of the ruling PML-Q, who has been engaged in a war of words with Bhutto over the past few days, urged her to trust the investigation being carried out by the country's agencies.

"Ironically, Benazir Bhutto relies on foreign police or investigators but did not have confidence in foreign courts when she asked for acquittal in the Swiss case," he told a press conference.