Pakistani Shia Muslims carry a coffin during a mourning ceremony for the victims of a blast in Rawalpindi, November 22, 2012.
At least seven Shia Muslims, including four children, have been killed and several others injured in a bomb attack in northwestern Pakistan.
The attack targeted a Shia procession held to commemorate the martyrdom of third Shia Imam, Imam Hussein (PBUH), in Pakistan's northwest district of Dera Ismail Khan on Saturday morning.
Security forces have been on high alert over fears of large-scale attacks on Shia Muslims across the country, as al-Qaeda-linked militants have threatened to carry out more attacks against Shias.
Heavily armed militants have targeted similar religious ceremonies in different regions of the country over the past week.
Intelligence information indicates more attacks have been planned for the coming days against Shias in the capital city of Islamabad, Karachi and Quetta.
In Karachi, more than 5,000 police are expected to patrol the streets during the processions on Saturday and Friday.
Violence has escalated against Shia Muslims in different parts of Pakistan in recent months. Since the beginning of 2012, hundreds of Shias have been killed in various parts of the country.
On Thursday, thousands of Pakistanis held funeral prayers for at least 37 Shia Muslims who were killed in coordinated serial bomb attacks across major cities of the country.
The funeral ceremonies were held a day after dozens of Shia Muslims had been killed in three bomb attacks on religious gatherings in the southern port city of Karachi and the garrison city of Rawalpindi on Wednesday evening.
Human rights groups say hundreds of Shia Muslims have been killed in the violence-hit country so far this year.
Pakistan's pro-Taliban militants have launched a violent campaign against Shia Muslims over the past years. According to local sources, militants affiliated to Taliban and al-Qaeda terrorist groups have killed thousands of Shia Muslims in the region since the start of the campaign.
The country's Shia leaders have called on the government to form a judicial commission to investigate the bloodshed.