"We have not seen this report, if that's out there. And we'll certainly look for it," White House Deputy Spokesman Tony Fratto said of reports of al-Qaeda having claimed the responsibility for slaying of Bhutto.

Immediately after her murder, the Pakistan government had blamed al-Qaeda for the attack by claiming that intelligence agents intercepted a message of congratulation from a Qaeda-linked militant leader Baitullah Mehsud.

Meanwhile, the United States again hailed the role of President Pervez Musharraf in the war on terror saying that it is important for Washington to have leadership in Islamabad -- whoever that may be -- which is committed to fighting terrorism.

"But as for President Musharraf, I don't think there's any question that he has been a very strong hand in fighting and a strong ally in fighting al-Qaeda and Taliban elements in Pakistan.