Protesters from a religious group blocked the main highway into Islamabad for the sixth day running on Monday, virtually locking down the Pakistani capital and causing commuter fury as authorities hesitated to act.
The roughly 2,000 protesters are demanding the resignation of the federal law minister over a hastily-abandoned amendment to the country's blasphemy laws.
They have camped for nearly a week on a flyover connecting Islamabad with the neighbouring garrison city of Rawalpindi, along which thousands of people commute every day to work in the capital.
Young men armed with clubs are searching anyone approaching the protest site and refusing to let vehicles pass, pelting those who come near with stones. 
"I have been stuck up on the road for (the) last one and a half hours because of this mess," said Adnan Iqbal, an employee of a pharmaceutical firm who spoke to AFP from the traffic jam where he was late for work.
The protesters, members of the Tehreek-i-Labaik Yah Rasool Allah Pakistan religious group, acted after the government introduced an amendment which changed some wording in the blasphemy law. 
The change -- from "I believe" to "I solemnly swear" -- did not alter the law, which carries the death penalty. The government has said the change was made inadvertently and quickly reversed it through another amendment.
But the rightwing group insisted it was an attempt to water down the hugely sensitive legislation.
"The protesters have baseless demands. Authorities should deal (with) them with force and move them away from the road," said Fayyaz Hussain, another commuter who had been struggling to reach his office for two hours on Monday.
Authorities were shying away from employing force despite the palpable anger of commuters and days of traffic delays.
"Use of force is no option at the moment," senior Islamabad official Shoaib Ali told AFP, adding that the priority was negotiations.
Protesters, meanwhile, vowed to stay put.
"Either the minister resigns or we are killed or arrested: we will not leave this place," Pir Muhammad Afzal Qadri, one of the group's leaders, told AFP at the protest site. 
The legislation has drawn criticism from human rights groups, who say it fuels extremism and is used to settle petty rows based on paltry evidence.