The Pakistan opposition political leader died Thursday at a political rally in the garrison city of Rawalpindi as she campaigned for parliamentary elections set for Jan. 8.

Interior Ministry spokesman Brig. Javed Iqbal Cheema told a news conference in Islamabad nothing entered Bhutto's head.

Cheema showed images of Bhutto in a car in which she was seen standing up through an open moon roof. He said when gunshots rang out followed by an explosion, the 54-year-old leader "fell down or perhaps ducked" and apparently hit her head on a lever, CNN reported. He said the lever was stained with blood.

Earlier reports carried by the official Pakistan news agency quoted the ministry saying that Bhutto was killed by shrapnel from the suicide bomb that went off as she stood up through the moon roof. At least 28 people died in the attack.

There had also been reports Bhutto was killed by bullets fired by the suicide bomber.

Cheema said Friday the government had an intelligence intercept showing al-Qaida was behind the attack, with a militant congratulating his followers for the assassination.

CNN reported the claim had not appeared on radical Islamist Web sites where such messages are routinely posted.