The Pakistani government has extended by 24 hours a deadline for an Islamic group to disband its rally in the capital.
Authorities had set a morning deadline of November 18 for the rally organizers -- the Tehreek-i-Labaik Ya Rasool Allah party -- to end a protest that has disrupted life in Islamabad.
Before dawn, police surrounded Islamabad's Faizabad crossing, where demonstrators have camped out.
They have been demanding the dismissal of the country's law minister, Zahid Hamid, who they charge intentionally removed a long-standing reference to the Prophet Muhammad from a constitutional bill.
Hamid has apologized, saying it was a clerical error that was later corrected. Interior Minister Ahsan Iqbal has dismissed what he called the protesters' "unreasonable demand" for Hamid's ouster.
On November 17, Khadim Hussain Rizvi, who runs the party behind the rally, told the gathering that he would not end his demonstration until Hamid is fired.
The rally has drawn criticism from residents in both Islamabad and Rawalpindi.
The police have put up shipping containers and road blocks to prevent the rally from pushing deeper into Islamabad.