Pakistani opposition leader Benazir Bhutto has been assassinated after a speech to thousands of supporters at a rally.
A party security adviser says Bhutto was shot in the neck and chest as she got into her vehicle, and then the gunman blew himself up.
Supporters learning the news have been smashing glass doors at the hospital where she died.
At least 20 other people were killed in the explosion.
Some have been voicing their anger at Pakistan's president Pervez Musharraf. Others have been weeping.
Bhutto had twice served as Pakistan's prime minister. She returned in October from an eight-year exile.
Bhutto assassination could bring outbreak of violence
There are fears that Pakistan could erupt in violence, after the assassination of opposition leader Benazir Bhutto.
A member of Bhutto's party who was at the hospital where she was taken confirmed her death. Bhutto's supporters exploded in anger, smashing the glass door at the main entrance of the emergency unit. Others burst into tears. Some began chanting that President Pervez Musharraf is a "killer." A few people outside began stoning cars.
The death of the charismatic former prime minister throws the campaign for next month's election into chaos.
Bhutto, who twice served as Pakistan's prime minister, had returned there from an eight-year exile in October. Her homecoming parade was also targeted by a suicide attacker, who killed more than 140 people.
US condemns Pakistan attack
The U.S. is condemning the attack in Pakistan that, according to aides to Benazir Bhutto, has killed the Pakistani opposition leader.
State Department spokesman Tom Casey says the attack "demonstrates that there are still those in Pakistan who want to subvert reconciliation and efforts to advance democracy."
For months, the United States has been encouraging Pakistan's president, Pervez Musharraf, to reach some kind of political accommodation with his opponents, particularly Bhutto.