Violence erupted in several cities across Pakistan following the assassination of former Prime Minister Benazir Bhutto at a campaign rally Thursday afternoon. Bhutto, 54, was shot in the neck and chest by a homicide bomber who then blew himself up, killing at least 20 others. Bhutto supporters immediately erupted in violence, attacking police and chanting slogans against President Pervez Musharraf. President Bush responds to the assassination.THE PRESIDENT: Laura and I extend our deepest condolences to the family of Benazir Bhutto, to her friends, to her supporters. We send our condolences to the families of the others who were killed in today's violence. And we send our condolences to all the people of Pakistan on this tragic occasion. The United States strongly condemns this cowardly act by murderous extremists who are trying to undermine Pakistan's democracy. Those who committed this crime must be brought to justice. Mrs. Bhutto served her nation twice as Prime Minister and she knew that her return to Pakistan earlier this year put her life at risk. Yet she refused to allow assassins to dictate the course of her country. We stand with the people of Pakistan in their struggle against the forces of terror and extremism. We urge them to honor Benazir Bhutto's memory by continuing with the democratic process for which she so bravely gave her life.