Benazir Bhutto, shown in a file photo, died in a suicide bomb and gun attack on Dec. 27. It's unclear whether a bullet or the impact of the bomb killed her. ((Anjum Naveed/Associated Press))

Two more suspects have been arrested in connection with the assassination of former Pakistani prime minister Benazir Bhutto, an official said Thursday.

Interior ministry spokesman Javed Iqbal Cheema said the two men were arrested in Rawalpindi, the same city where Bhutto died in the Dec. 27 gun and suicide bomb attack.

"These are important arrests," Cheema was quoted by Reuters as saying.

The men are scheduled to appear in an anti-terrorism court Friday, said Cheema, but he declined to say whether they were directly implicated in the assassination. No further details were provided.

Last month, Pakistani authorities announced they'd arrested two other suspects, including a 15-year-old boy alleged to have been part of a suicide squad assigned to kill Bhutto.

U.S. and Pakistani officials have said they believe the assassination was masterminded by Baitullah Mehsud, an alleged al-Qaeda commander. Mehsud's purported spokesman has denied the accusations.

Final day of mourning period

Thursday also marked the end of the 40-day mourning period following Bhutto's death, and an estimated 10,000 of her followers gathered outside the family's mausoleum in the southern province of Sindh.

With the mourning period finished, Bhutto's Pakistan Peoples Party, now led by her widower, Asif Ali Zardari, plans to resume campaigning for the Feb. 18 parliamentary elections, which were postponed six weeks due to her death.

Opponents of the PPP are hoping the sympathy vote for Bhutto will have subsided by the time the country heads to the polls.

President Pervez Musharraf was re-elected last October but requires a strong majority in parliament to fend off demands for impeachment.

White House officials have lauded Musharraf as a key ally in the so-called war on terror, but the former general's support has been eroding.

Even retired generals have joined lawyers and others calling for Musharraf to step down.

Meanwhile, Scotland Yard investigators invited to probe Bhutto's killing have returned to Pakistan to present their conclusions on Friday.

The three-member British team was asked to resolve exactly how Bhutto died. There has been confusion over whether she was killed by a gunshot or the impact of the suicide bombing that followed.

With files from the Associated Press