Interior Ministry spokesman Javed Iqbal Cheema said the two men were arrested in Rawalpindi, where Bhutto died in a gun and bomb attack on Dec. 27, but gave no further details. Last month, authorities in northwestern Pakistan said they had arrested two other suspects, including a 15-year-old boy who was alleged to have been part of the suicide squad assigned to kill her.
U.S. and Pakistani officials believe the assassination was masterminded by Baitullah Mehsud, an al Qaeda-linked commander based in South Waziristan. Mehsud is the leader of Tehrik-e-Taliban Pakistan, a militant umbrella group that has been battling government forces in the remote, rugged tribal area along the border with Afghanistan.
On Wednesday, the Taliban announced an indefinite cease-fire with Pakistani forces. President Pervez Musharraf's government did not confirm a truce, but Interior Minister Hamid Nawaz said the national leadership was ready for a dialogue with the Taliban.
Two Pakistani officials said Thursday that their government held secret talks with Taliban fighters and tribal elders near the Afghan border before the cease-fire. The officials, who were familiar with the talks, said they took place at an undisclosed location in South Waziristan, a semiautonomous region that is home to scores of al Qaeda and Taliban fighters.
The officials would not say who represented the government or how long the dialogue had been going on.
The militant representatives included Siraj Haqqani, a prominent Afghan militant blamed for attacks against coalition forces in Afghanistan, one official said. Both officials spoke on condition of anonymity because of the sensitivity of the issue.
Bhutto's party condemned any dialogue between the government and Taliban militants.
"The government is holding talks with the man blamed by it for the killing of Benazir Bhutto. We condemn it," spokeswoman Sherry Rehman said.
Rehman spoke in the southern province of Sindh, where an estimated 10,000 Bhutto followers gathered to mark the end of the 40-day mourning period for her death. After Thursday's religious ceremonies, Bhutto's party, now led by her husband Asif Ali Zardari, is set to resume campaigning for crucial Feb. 18 parliamentary elections, which were delayed for six weeks after her death.
A three-member team of British investigators from Scotland Yard arrived in the capital early Thursday to share with Pakistan the findings of their probe into exactly how Bhutto died - amid confusion over whether she was killed by a gunshot or the impact of the suicide bombing that followed as she left an election rally by her Pakistan People's Party in Rawalpindi.
Aidan Liddle, spokesman for the British High Commission, said it would release a summary of the report on Friday.
Bhutto's violent death has put a damper on public campaigning for the upcoming elections, aimed at restoring civilian government after eight years of military rule. Musharraf was re-elected president in October but needs a strong majority in Parliament to fend off demands for his impeachment.
White House officials have lauded Musharraf as an indispensable ally in the U.S. war on terror. But the former general has seen his support among Pakistanis steadily erode. Even retired generals have joined lawyers and other professionals in demanding he step down.
A truce with the Taliban may help the government maintain order during the Feb. 18 balloting, although numerous other extremist groups throughout the country may not consider themselves bound by the truce.
But any deal that allows armed Islamic extremists to operate on Pakistani soil would run counter to U.S. demands for the government to crack down on militants. The U.S. contends a failed truce last year allowed al Qaeda to expand its reach into the turbulent, nuclear-armed country, and the U.S. has sounded warnings in recent days about a revival of militant strength.
Militant spokesman Maulvi Mohammed Umar said the truce includes the tribal belt along the Afghan border and the restive Swat region to the east where the army has also battled pro-Taliban fighters.
The Pakistani government has repeatedly tried to strike peace deals with local pro-Taliban militants, urging them to expel foreign al Qaeda militants the U.S. has warned may use sanctuaries inside Pakistan's tribal regions to plot terror attacks around the globe.
Musharraf, however, faces opposition from a broad array of groups, including mainstream lawyers, intellectuals and professionals.
On Thursday, a private TV news station accused the government of blocking its transmissions after it aired a program featuring a critic of Musharraf. The satellite transmission of Aaj television was blocked late Wednesday after commentator Nusrat Javed appeared on-screen, said Aslam Dogar, an assignment editor at the station.
The government denied it had shut down the station, which was back on the air Thursday after more than 12 hours. Aaj television was also banned in November when Musharraf declared a state of emergency and put curbs on the media.
Elsewhere, three men were killed and 13 others wounded when a bomb exploded Thursday in southwestern Baluchistan province. The blast occurred near a bus station in a bazaar in the town of Dera Murad Jamali, local police officer Ghulam Mustafa said.