The riot police arrested dozens of people and fired teargas shells and used batons to break up a march organised by a religious group to protest the Taliban bombings in Pakistan, organisers and witnesses said.
Several hundred activists from sunni muslim groups started the "Long March" from Islamabad on Saturday and planned to go to Lahore, the capital of Punjab province.
The Punjab government had banned the rally, fearing it could be attacked by militants. Despite the ban, around 200 activists of the sunni ittehad council succeeded in marching from Islamabad to the garrison city of Rawalpindi.
The march was aimed at protesting against recent Taliban attacks on shrines of sufi saints, council leader Hanif Tayyab said.
Police parked containers on the main highway between Rawalpindi and Lahore to stop the marchers who were on foot and in vehicles, Tayyab said.
When the marchers succeeded in crossing barriers, police in Rawalpindi used teargas and batons to stop them from proceeding to Lahore.
Witnesses said participants threw stones at the police, turning parts of Rawalpindi into a battleground.
Several participants damaged a police van, officials said.
In Punjab, police launched a crackdown and arrested dozens of activists of sunni muslim groups from different districts of the province.
Leaders of the sunni ittehad council claimed police had arrested 5,000 of its workers during the past three days but this could not be independently confirmed.
Council spokesman Muhammad Nawaz Kheral said the police had sealed several religious seminaries in Punjab by deploying scores of policemen. He said this was a matter of great concern for his organisation.
Officials said that the march was banned following reports of a possible attack on the march by militants.
Despite the restrictions imposed by the authorities, leaders of the sunni ittehad council vowed to continue the protest in Lahore.
"We will try to reach Lahore to stage a protest there," Tayyab said.