Pakistani officials have quietly begun consulting with other nations about the conduct of their investigation into opposition leader Benazir Bhutto's killing, despite a public insistence that they need no foreign help, U.S. officials say.

Pakistan President Pervez Musharraf is under pressure to respond to accusations from Bhutto's aides of a government cover-up. While his government has rejected the idea of an outside investigation, Pakistan's consultations with other countries suggested it was concerned that its own probe to be seen as credible.

The U.S. officials said it was still not entirely clear whether Pakistan was seeking international assistance in an investigation, or simply wanted backing from other countries as it conducts its own probe.

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"The Pakistan government is discussing with other governments as to how best the investigation can be handled," said one senior U.S. government official, speaking on condition of anonymity because no agreement had yet come from the discussions.

The suicide attack that killed Bhutto on Thursday sparked three days of unrest that have left more than 40 dead and tens of millions of dollars in damage, with security forces now authorized to shoot rioters on sight.

With the United States, the official said, the discussions about investigating Bhutto's assassination "are about what we can offer and what the Pakistanis want. Having some help to make sure international questions are answered is definitely an option."

Pakistan has launched up to three separate domestic "inquiries" into Bhutto's death and is waiting to see how those go before making any decision on whether to see formal international assistance, a U.N. Security Council diplomatic official told the AP.

The U.S. official, however, said the Pakistanis "don't want the U.N. involved in this."

The council voted Thursday to condemn her killing and urge all nations to quickly help bring those who did it to justice.

"Of course the government would not be adverse to using any kind of information or technical assistance which may lead to finding the perpetrators who have committed this heinous crime," Jalil Shafqat, a spokesman for the Permanent Mission of Pakistan to the U.N., told the AP.

Pakistan Interior Ministry spokesman Javed Iqbal Cheema said one of the investigations should be completed within seven days of a judge being appointed to oversee it.

"This is not an ordinary criminal matter in which we require assistance of the international community. I think we are capable of handling it," he said.

FBI Special Agent Richard Kolko told the AP that any request for the FBI to help with the probes would come through the U.S. Embassy in Pakistan to the State Department.

But the FBI is already involved. Two days ago, a national FBI and Department of Homeland Security bulletin to law enforcement agencies cited Islamist Web sites as saying al-Qaida had claimed responsibility, Kolko said.

"The FBI and DHS continue to work with our U.S. intelligence community partners to assess the al-Qaida claims for any intelligence value," he said. "The validity of those claims continues to be reviewed."

State Department spokesman Thomas Casey told the AP the United States is "willing to assist Pakistan in whatever way we can with the investigation. However, to date Pakistan has not made any formal request."

British Foreign Secretary David Miliband offered his country's help. U.S. presidential candidate Hillary Rodham Clinton and a Belgian think-tank each suggested that the U.N. Security Council might want to investigate. U.S. presidential candidate John McCain cautioned, however, that may not be needed.

Diplomats say there is little chance of that happening. The council's investigation into the assassination of former Lebanese Prime Minister Rafik Hariri "shows you that even when the government wants one, it can be quite difficult," one Security Council diplomat said. The Hariri investigation has not still concluded nearly three years after his February 2005 death.

The Security Council's resolution on Thursday deleted, at Pakistan's insistence, language seeking to encourage more dialogue and national unity within Pakistan and to bring Bhutto's killers to justice as soon as possible.

"It's all about the language and choice of words," Jalil said.

Pakistan was very concerned about the resolution, according to three security council diplomats, because it did not want the council meddling in their affairs and the language could have implied that Musharraf's government was not acting quickly enough.