The Pakistan police on Friday claimed they had arrested another important suspect, allegedly involved in the assassination of former premier Benazir Bhutto, taking the total number of people apprehended in the case to five.

Abdur Rashid Torabi, who was produced in an anti-terrorism court in Rawalpindi under tight security, confessed to his involvement in the assassination before the judge.

Additional Inspector General of Police Chaudhry Abdul Majeed, the official heading the Pakistani team probing Bhutto's killing, described Torabi as an 'important suspect'.

Majeed said Torabi was not part of the five-member squad that went to target Bhutto after she addressed an election rally at Liaquat Bagh in Rawalpindi on December 27, but did not give further details.

The police did not say where or when Torabi had been arrested. It is believed the suspect was involved in planning the assassination and providing arms to the killers.

Authorities have so far arrested four persons including 15-year-old Aitezaz Shah, Sher Zaman, Hasnain Gul and Rafaqat for their alleged involvement in the assassination. They are also looking for Ikramullah, one of the two suicide bombers who went to Liaquat Bagh to kill Bhutto.

Gul and his cousin Rafaqat, who were arrested in Rawalpindi, have told police that a suicide bomber named Bilal fired shots at Bhutto and then blew himself up near her armoured vehicle. Ikramullah, who was to have targeted Bhutto if she survived the blast triggered by Bilal, had gone to the troubled Waziristan tribal region a day after the killing.

Bhutto's Pakistan People's Party has said that it is not satisfied with the probe into the assassination and demanded a United Nations-led inquiry to expose the 'hidden hands' that planned and sponsored her killing.