The army in Pakistan has claimed it is ready to step in after protests spread from Islamabad to a number of other cities.
Islamist protesters began blocking a highway in Islamabad over a fortnight ago against the changing of the wording for an electoral oath, which was quickly rectified.
Over the weekend other groups in cities including Lahore and Karachi took up the protest, demanding the sacking of Law Minister Zahid Hamid, whom they accuse of blasphemy.
At least six people are believed to have been killed in clashes, with around 200 injured.