Former Pakistani Prime Minister Benazir Bhutto, who recently returned to the country to challenge the Pervez Musharraf regime, has been assassinated in a suicide attack which has killed 20 others and injured several more.
Shock, mourning, anger and rioting have been following in the wake of the tragic events, which took place when Ms Bhutto - the first woman PM in an Islamic state - was leaving an election rally in Rawalpindi.
A gunman shot her in the neck and set off a bomb, reports the BBC and press agencies. President Musharraf, who had placed Ms Bhutto under house arrest when she flew back into the country in October 2007, condemned the killing.
The authorities were tonight urging people to remain calm but furious protests have already gripped cities and neighbourhoods across Pakistan. Security forces have been placed on a state of "red alert" nationwide, and commentators say that the country is on "a knife edge".
There were no immediate claims of responsibility for the attack. Analysts believe hardline Islamist militants to be the most likely suspects.
Ms Bhutto, leader of the Pakistan People's Party (PPP), had served as prime minister from 1988-1990 and 1993-1996. She was seen as signalling a new kind of Pakistan with an emphasis on democracy, participation and women's rights. But she also faced charges of corruption, manipulation and cosying up to the West.
The former PM and had been campaigning ahead of elections due on 8 January 2008. There is some likelihood that these may now be postponed or suspended, depending on how events unfold over the next few days.
The attack that killed Ms Bhutto was the second suicide assault against her in recent months and came amid a wave of bombings targeting security and government officials.
Speaking on Channel 4 TV in Britain, radical commentator Tariq Ali said that he was shocked and angered at the assassination, but suggested that there were "serious problems" with s Bhutto's rule and said that history "should not be re-written" in the wake of sorrow and anger at her killing.
British PM Gordon Brown was among the many world leaders who united to condemn the killing. US President George W. Bush also broke from his vaction to make a statement.