Violence erupted in two Pakistani cities yesterday, compounding the woes of Pervez Musharraf, the military ruler, just as he is under intensifying pressure from his neighbours and Washington to crush Islamist militancy.
The general's security forces were on alert last night amid fears of an explosion of bloodshed between Sunni and Shia Muslims after the assassination of Azam Tariq, the leader of a banned Sunni group and parliamentarian, on Monday.
Mr Tariq's supporters, many of them religious students, rampaged through the usually quiet capital, Islamabad, smashing cars and shop windows, and setting fire to a Shia shrine and one of the city's few cinemas. They also ran amok in Mr Tariq's stronghold, the city of Jhang in Punjab, where his body was flown by helicopter for burial. They burnt down a Shia mosque and destroyed a petrol station. Some 25,000 people gathered in a sports stadium to mourn his death; Shots rang out in the crowd.
Pursued by police firing shots into the air, rioters in both cities chanted anti-Shia slogans and vowed to avenge the death of the Sunni leader, killed when gunmen opened fire on his car in Islamabad, which also left his driver and three bodyguards dead.
The assassination occurred on the same day that General Musharraf was assuring his latest foreign visitor, Richard Armitage, the US Deputy Secretary of State, that Pakistan was doing everything possible to contain Islamist militancy in the name of what Washington calls its "war on terror".
The Americans want the general to do more to stifle Islamist groups who are dispatching guerrillas from Pakistan's remote western borders to mount attacks in Afghanistan on US troops and against the soldiers and police representing the threadbare US-backed interim government of Hamid Karzai.
There is pressure, too, to clamp down on militants infiltrating from north-east Pakistan into Indian-administered Kashmir, where hundreds are dying every month in battles between anti-India Islamists and security forces.
Neither task is easy, given the support enjoyed by the religious parties, particularly in the borderlands, the unpopularity of the Americans, even among Pakistan's powerful intelligence apparatus, and the strong national sentiments over Kashmir.
But the general's problems do not stop there: Sectarian violence between Sunnis and Shias has led to many hundreds of deaths in recent years. Worries abound that another bout of bloodletting is imminent.
Tension has been building for weeks. This summer has seen several attacks, including the death of more than 50 worshippers in Quetta when suspected Sunni gunmen sprayed a Shia mosque. On Friday, six Shias were killed in an attack on a bus in Karachi.
By nightfall yesterday, the death toll from the day's unrest stood at four, of whom three were soldiers killed when their vehicle crashed en route to contain the trouble in Jhang.
Mr Tariq was the leader of the Sipah-e-Sahaba (Guardians of the Friends of the Prophets), a group which Pakistan believes is responsible for more than 400 sectarian killings. In an e-mail to journalists yesterday, a previously unknown Shia group claimed responsibility for killing him.
After 11 September, 2001, General Musharraf banned Mr Tariq's organisation, which has ties to the Taliban, and he was thrown in prison. In last year's elections, Mr Tariq contested a seat in Pakistan's largely powerless parliament from his prison cell and was elected.
Shortly afterwards, he was released on the orders of a court in Lahore which ruled that the state did not hold enough evidence to detain him. He became a supporter of Zafarullah Khan Jamali, General Musharraf's prime minister.
The violence in Islamabad day occurred after thousands of his supporters attended prayers where they vowed to take up Mr Tariq's struggle against the minority Shias.