The government in Bhutto's home province of Sindh denied her party had been targeted, but said around 1,000 people had been arrested on a range of charges stemming from rioting that broke out after her Dec. 27 assassination, which left 60 people dead and caused tens of millions of dollars in damage.
"The common people suffered a lot of damage to their property and whoever is responsible for this will be dealt with in accordance with the law," said Akhtar Zamin, Sindh's interior minister. "We have nothing to do with anyone's party affiliation. We are objectively investigating to sort out the real culprits."
Visiting U.S. Sen. Joseph Lieberman said President Pervez Musharraf had assured him the parliamentary polls would take place as scheduled on Feb. 18, but acknowledged that opposition parties had little trust that the elections would be fair.
"I hope this distrust will be proven wrong," Lieberman, an independent from Connecticut, told reporters. Unfair elections "will increase divisions, not the unity that the country needs." Lieberman met with Musharraf, military leaders and opposition politicians on his brief trip.
The claims of a police crackdown on Bhutto's supporters are sign of rising tensions ahead of elections, which opposition parties claim President Pervez Musharraf is already intent on rigging. Musharraf denies the charge.
Latif Khosa, a senior senator from Bhutto's party, told reporters that police had filed charges against 400,000 of its supporters nationwide and arrested "thousands" of others.
Khosa alleged the arrests were to prevent Bhutto supporters "from taking part in the election process."
Musharraf blames Islamic militants for Bhutto's killing, which thrust Pakistan even deeper into political crisis at a time when it is battling fighters linked to al Qaeda and the Taliban movement.
But many opposition politicians and other government critics have alleged elements of his government were responsible, either directly or by failing to provide her with decent security.
A small team of officers from Britain's Scotland Yard are working with Pakistani police in the investigation.
Officers from the team have so far examined the car that Bhutto was traveling in when she was attacked, interviewed witnesses and scoured the crime scene, but have made no public statement.
On Wednesday, they traveled to the eastern city of Lahore where they intend to examine two pistols and some other material recovered the crime scene at a police forensic laboratory there, said Pakistani police forensic expert Amir Ali Hussain.