Pakistan opposition leader Benazir Bhutto - who spoke in Rapid City in 2003 as a guest of the John T. Vucurevich Foundation - was assassinated Thursday in a suicide attack at a campaign rally that also killed at least 20 others, aides said.

Bhutto's supporters erupted in anger and grief after her death, attacking police and burning tires and election campaign posters in several cities. At the hospital where she died, some smashed glass and wailed, chanting slogans against President Pervez Musharraf.

The death of the charismatic 54-year-old former prime minister threw the campaign for the Jan. 8 parliamentary elections into chaos and created fears of mass protests and violence across the nuclear-armed nation, an important U.S. ally in the war on terrorism.

Bhutto had rallied vigorously against Islamic terrorism, and told a Rapid City audience in 2003 that if her moderate, democratically elected government had been running Pakistan, the terrorist attacks of Sept. 11, 2001, might never have happened. The two-time former prime minister of Pakistan, a charismatic world leader who never lacked political confidence, argued that her continued leadership would have countered the rise of the Islamic militants who masterminded 9-11.

Osama bin Laden and other terrorists thrived after 1996, the year she was ousted from power the second time, Bhutto told the 1,500 people gathered at the Rushmore Plaza Civic Center. As an Islamic politician, she was aware of the growing anti-United States sentiment in the Islamic world, but as a moderate, she stood against it.

After the mujahedeen defeated the Soviet Union in Afghanistan, she knew that Islamic militants believed that if they could defeat one world superpower, they could wage and win a war of terror against the United States, as well. "I argued against that position," she said. "I was a dangerous obstacle to the forces of hate. I took them on, and my government paid the price."

Bhutto took aim at her political rival, President Musharraf, a general who took power in a military coup in 1999. She credits Musharraf for his alliance with the Bush administration but continues to be troubled by his "military dictatorship of my country" and the U.S. backing he receives to continue it. She called his election a "mockery of justice" and said his dictatorship is "strangling our constitution."

"I'm troubled by Gen. Musharraf's administration," she said. "He makes all the right noises … but is somehow unable to deliver on the ground."

The United States should not believe that the only chance for political stability in an Islamic country is a military dictatorship, she said. That is the message Musharraf sends, and it is the wrong one, she believes.

"It is not a choice between military dictatorship or religious dictatorship," she said of Islamic countries such as her own. "Islam supports democracy, so I find it ironic that most Muslim countries today live under dictatorship."

Musharraf condemned the assassination of Bhutto and urged calm, according to the state-run Associated Press of Pakistan. He also convened an emergency meeting with his senior staff, where they were expected to discuss whether to postpone the elections, an official at the Interior Ministry said, speaking on condition of anonymity because of the sensitivity of the talks.

No one claimed responsibility for the killing but suspicion was almost certain to fall on Islamic militants.

The attacker struck just minutes after Bhutto addressed thousands of supporters in the garrison city of Rawalpindi, 8 miles south of Islamabad. She was shot in the neck and chest by the attacker, who then blew himself up, said Rehman Malik, Bhutto's security adviser.

Sardar Qamar Hayyat, a leader from Bhutto's party, said he was standing about 10 yard away from Benazir Bhutto's vehicle at the time of the attack.

"She was inside the vehicle and was coming out from the gate after addressing the rally when some of the youths started chanting slogans in her favor. Then I saw a smiling Bhutto emerging from the vehicle's roof and responding to their slogans," he said.

"Then I saw a thin, young man jumping toward her vehicle from the back and opening fire. Moments later, I saw her speeding vehicle going away," he added.

Bhutto was rushed to the hospital and taken into emergency surgery. She died about an hour after the attack.