Ms Bhutto's death leaves a vacuum in Pakistan's shaky political system.

As if things could not get worse in a country that has been torn apart by political strife and Taleban extremism in recent months, Pakistan has now been plunged into unimaginable grief, anger and chaos and an uncertain political future.

The killing of Benazir Bhutto will probably lead to the cancellation of national and provincial elections on 8 January.

With rioting across the country, it could also lead to the imposition of extraordinary measures by the military - a state of emergency or even martial law.

Ms Bhutto died just two miles from where her father, former Prime Minister Zulfiqar Ali Bhutto, was hanged by a former military dictator 30 years ago.

There has been a bitter feud between the military and the Bhutto family-led Pakistan People's Party (PPP) ever since.

On Thursday party stalwarts were accusing the military of perpetrating the latest murder of a Bhutto - although that is extremely unlikely.

After Benazir Bhutto no politician or party is prepared to face up to the threat posed by Islamic extremism Send your views on the article

The classic use of a sniper and a suicide bomb attack to cut her down bore all the hallmarks of an al-Qaeda trained Pakistani suicide squad.

The personal tragedy for this family - Ms Bhutto's two brothers also died violently, one was poisoned, the other shot - has epitomised the footprints of Pakistan's bloody political scene since its inception in 1947.

Pakistan's first Prime Minister, Liaquat Ali Khan, was assassinated at a political rally nearly 60 years ago at the exact spot where Bhutto died.

Vacuum

Her death leaves the largest possible vacuum at the heart of Pakistan's shaky political system.

Twice elected prime minister, twice dismissed on charges of corruption and incompetence by the military, Ms Bhutto was still a giant of a politician in a land of political pygmies and acolytes of the military.

'Ms Bhutto was a giant in a land of political pygmies'

Ms Bhutto looked set to win the general elections in January. Earlier this year she and President Pervez Musharraf had been planning to work together with the army to curb the threat of extremism that Pakistan now faces.

Instead the country now seems to be slipping into an abyss of violence and Islamic extremism.

It was clear weeks ago that President Musharraf did not want to work with her, despite pressure from the Americans to do so.

He and the army have been siding emphatically with his former allies in the Pakistan Muslim League-Q (PML-Q) and he was doing everything possible to make sure that they would win the elections.

Public anger at President Musharraf stems from not just the fact that the government failed to provide adequate security for Ms Bhutto, but that the government and army were never impartial and appeared all set to try to rig the elections against her Pakistan People's Party (PPP).

Rhetoric

More critical to Pakistan's future stability is that after Ms Bhutto no significant politician or party looks prepared to face up to the threat posed by Islamist extremism and the Pakistani Taleban who today are the main threat to the state.

In recent weeks she had confronted the Taleban extremists head on.

'Musharraf may not survive the fallout of Ms Bhutto's death'

In a country where the only recent political advances have been made by the Pakistani Taleban, who have seized large chunks of territory, such a role was an immensely brave and necessary one.

Moreover, Ms Bhutto had the political base to conduct a war against extremists.

She commanded the diehard loyalty of at least one third of the electorate, who were vehemently against army rule and the Islamist extremists. The PPP is the closest the Islamic Republic of Pakistan has ever got to espousing a secular, democratic political culture.

President Musharraf may simply not survive the fallout of Ms Bhutto's death.

His crackdown last month on Pakistan's fledgling civil society was unacceptable to large parts of the population who saw lawyers, journalists and women being hauled off to jail. No Islamist fundamentalists were rounded up when he declared a state of emergency on 3 November.

In the present state of grief and shock, it is unlikely that other opposition leaders will want President Musharraf to stay on in office.

If the rioting and political mayhem worsens, if the opposition refuses to co-operate with him and the international community finally begins to distance itself from him, then the army may be forced to tell President Musharraf to call it a day.

Should that happen it is imperative that world leaders insist upon a return to civilian rule and elections and not another military dictatorship.

Ahmed Rashid is a Pakistani journalist based in Lahore. He is the author of three books including Taliban and, most recently, Jihad. He has covered Pakistan, Afghanistan and Central Asia for the past 25 years.

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