Pakistan's Shia-Sunni divide

Sectarian violence is one aspect of extremism

By BBC News Online's Mahmud Ali

The explosion at the Shia mosque in Bhakkar has been described by local officials as a "sectarian attack" against the minority Shia community.

Sectarian tensions are high during Muharram

Differences between Pakistan's Sunni majority and Shia minority go back to the Islamic schism following the prophet's death.

But the past two decades have been especially violent.

Sunni militants are thought to be behind attacks on Shia doctors in Karachi, and an attack on a Shia mosque in Rawalpindi recently led to the death of many worshippers.

Religious politics

Most analysts agree the current hostilities began in 1979 when military dictator General Zia ul-Haq began Islamising Pakistani politics to legitimise military rule.

As a result, hardline religious groups were strengthened.

Lethal weapons are widely available

Following the Soviet invasion of Afghanistan in late 1979, US arms and Saudi funds allowed General Zia to mount a proxy war in Afghanistan with mujahideen, or holy warriors.

Drawn from Pakistani as well as Afghan and Arab youths mostly educated at religious schools, the Mujahideen and their patrons were to become influential actors in Pakistan.

Because Sunnis form a large majority in Pakistan, most of the mujahideen were Sunni too.

Radical Sunni Islamists were able to establish armed groups like the Sipah-e-Sahaba and Tanzeem-e-Nifaz.

Revolutionary zeal

Shia fighters too joined the jihad against the Soviets in Afghanistan, although their bands were smaller.

Violence has been endemic for years

They received help from Iran where the Islamic revolution earlier in 1979 had boosted Shia confidence.

The growth of Shia militancy led to the establishment of groups such as Tehrik-e-Jafaria.

Once the Soviets left Afghanistan, Pakistani militants returned home and began looking for a new jihad.

Many were encouraged to take their combat skills to Indian-administered Kashmir.

Others stayed home to begin a campaign against fellow-Muslims they considered heretics.

Political will

As a result, Sunni and Shia militant groups have been at the forefront of Pakistan's sectarian conflict.

When President Musharraf launched his campaign against extremism, he banned groups noted for violent attacks against their sectarian opponents.

But recent attacks have shown the limitations of the government's policy.

Some analysts say that, having used the Islamists for their own ends, Pakistan's security establishment would have difficulty in switching off the violence just because it is getting too close for comfort.

Others say Pakistan's unrepresentative ruling elites have an interest in keeping the population divided and the sectarian rift serves them well.