The Pakistani authorities have issued a security alert in Karachi and several cities in Punjab province to avoid sectarian violence during the Shi'a holy month of mourning.

Regular army troops and paramilitary units have been deployed in many cities following a number of relatively minor incidents of armed attacks on Shi'ite gatherings in which several people have been injured.

Large-scale mourning processions marking the martyrdom of the Prophet Mohammad's grandson, Imam Hussein, fall on 10th of the Muslim month of Moharrum, next Tuesday.

Attacks on the increase

According to police, several people were injured in Multan when gunmen attacked a Shi'a gathering two days ago.

A dozen more people were injured in Karachi on Friday night, when unidentified persons threw a grenade inside a Shi'a mosque.

Several more people have been hurt in a number of other related incidents for which the authorities blame an extremist Sunni Muslim group.

Senior officials say although these are relatively minor incidents, they are not taking any chances.

Security stepped up

The tension between Islamic groups increases during the Muslim month of Muharrum.

Army troops have been called out in several cities in Punjab province, where there is a history of sectarian trouble.

And paramilitary troops are being deployed in many other parts of the country in preparation for the mourning processions.

Sectarian rivalry between the extremist groups of the majority Sunni and minority Shi'ite Muslims has already resulted in more than 200 deaths in the last couple of years.