Trouble erupted at rallies in the capital Islamabad and the eastern city of Lahore as cleric Agha Ziauddin was being buried in the remote northern town of Gilgit on Friday, where he was ambushed and fatally wounded last week.
The minority Shia leader died in a military hospital in Rawalpindi, near Islamabad, on Thursday, four days after he was brought there by helicopter from the Himalayan gateway town of Gilgit for treatment.
Police shot dead a man for breaking a curfew in Skardu on Friday but the incident was not linked to any unrest, local officials said.
All telephone lines to Skardu appeared to have been cut off, an AFP correspondent said.
Skardu and neighbouring Gilgit have been under 24-hour curfew and troops have been patrolling the streets since Saturday, when the attack on Ziauddin triggered an outbreak of sectarian violence in which 15 people were killed.
About 5000 people attended the Shia leader's funeral late on Friday at the main mosque in Gilgit, where he was a preacher, after his body was flown back to the town, residents said.
Shia activists held protests after
the funeral of Ziauddin
One of his bodyguards who was wounded in the attack and died in the same hospital on Thursday was buried at the same time.
Authorities have beefed up security across the country.
Sectarian bloodshed involving rival Sunni and Shia extremists has claimed more than 4000 lives since late the 1980s. Shia form about 20% of Pakistan's 150 million population but are in a majority in Gilgit and Skardu.
About 200 people from the Imamia Student Organisation, the Shia youth wing, rallied in Islamabad, where police used tear gas and batons to disperse them after they allegedly hurled rocks at officers, witnesses said.
Police rounded up dozens of students and took them away in police vans from the city centre after the clash, they said.
About 600 angry members of the same Shia group rallied outside the press club in Lahore, Pakistan's second largest city, where they were involved in a row with journalists after they blocked entry to the premises.
Police took about 200 of the
protesters into custody
Witnesses said the demonstrators threw stones at the club building and also roughed up journalists, injuring five. They also destroyed media vehicles parked on the premises.
Police swooped on the protesters as they were leaving the area and took about 200 of them into custody, an AFP correspondent at the scene said.
Gilgit has a history of sectarian violence but the weekend disturbances were the worst since several people were killed in June last year.
Authorities have helped 36 foreigners - 14 South Koreans, five Chinese, one Japanese and 16 Afghans - to leave Gilgit, local officials said. Seventy Chinese engineers working on a hydroelectric project have also been moved.
Unrest erupted on Thursday after Ziauddin's death was announced, with mobs in Skardu torching a Sunni school and ransacking a Pakistan International Airlines office.
Investigators have said one of Ziauddin's alleged killers, who died in the shoot-out, belonged to a banned Sunni militant group.