The British government Sunday asked its staffers in Islamabad and Karachi to "limit their non-essential movements" in wake of countrywide protests by activists of Tehreek-e-Labaik .

"There are currently reports of unrest in some cities in Pakistan, particularly Rawalpindi, Lahore and Karachi," the government said in a statement.

"There are unconfirmed reports of disruption at Islamabad International Airport."

Tehreek activists clashed with security forces for a second day outside the capital, Islamabad , burning vehicles before withdrawing into an uneasy stand-off at a protest camp they have occupied for two weeks.

According to media reports at least six people were killed on the previous day, when several thousand police and paramilitary forces tried to disperse the religious hardliners, who have blocked the main route into the capital demanding that the law minister be fired for committing blasphemy.

At least 150 people were wounded in Saturday’s clashes, hospitals reported, and police superintendent Amir Niazi said 80 members of the security forces were among those casualties.

Throughout Sunday, baton-armed supporters of the party blocked several main highways, roads and arteries in major cities, paralysing traffic and daily life.

The government has decided to resume negotiations after a high-level civil-military huddle agreed on "no use of force on fellow Pakistanis".

Led by cleric Khadim Hussain Rizvi, Tehreek-e-Labaik is one of two new ultra-religious political movements that became prominent in recent months. The party, which campaigns on defending Pakistan’s strict blasphemy laws, won a surprisingly strong six per cent and 7.6 per cent of the vote in two recent by-elections.