At least 100,000 hardline Islamists demanding a new blasphemy law blocked major highways on Sunday cutting off the Bangladeshi capital Dhaka from the rest of the country, police said.
Chanting "Allahu Akbar!" ("God is the greatest!"), activists from Hefajat-e-Islam marched down at least six highways, stopping road transport between Dhaka and other cities and towns.
Hefajat held the mass protest to push for a 13-point list of demands which also includes a ban on men and women being able to mix freely together and the restoration of pledges to Allah in the constitution.
The newly created radical Islamist group is also calling for the death penalty for those who defame Islam.
Police fired rubber bullets and tear gas at thousands of Hefajat activists to disperse them as they entered Dhaka, an AFP photographer at the scene said. There were no reports of injuries.
The demonstrators plan to gather for a rally in the capital later today.
Ismail Hossain, police chief at Tongi town, which links Dhaka with northern Bangladesh, told AFP that "at least 100,000 Hefajat activists" had been blocking the main highway since dawn.
"They are peaceful. We don't have any report of violence," he said.
Marchers also blocked highways at Jatrabari and Demra, cutting the city off from the north-east and south-east, including the main port city of Chittagong.
The major rally is the latest in a series of mass actions by Hefajat to increase pressure on the government to meet its demands.
Last month activists organised a general strike as well as a gathering of hundreds of thousands of its activists, who rallied in Dhaka in what experts said was the largest political gathering in decades.
Critics have branded Hefajat's demands as a charter for turning Bangladesh into a country like Taliban-ruled Afghanistan.
Women workers including female garment labourers have vented their anger at the group's call to segregate the genders.
Hefajat also wants Islamic education to be made mandatory in primary and secondary schools and restrictions on Christian missionaries.
Bangladesh's Prime Minister Sheikh Hasina, who has been leading a secular government in the Muslim-majority country since 2009, said on Friday that she had rejected the blasphemy law and that existing laws were adequate to prosecute anyone accused of insulting Islam.
Hasina's ruling Awami League party has accused Hefajat, which draws its support from the country's tens of thousands of Islamic seminaries, of being a pawn of the opposition, which has lent moral support for Sunday's blockade.
Hardline Islamist groups say Hasina's government is trying to intimidate the opposition through a series of trials for war crimes allegedly committed during the 1971 war of independence.
Three Islamists have so far been convicted and two of them were sentenced to death. At least 96 people have been killed during protests over the trials since January.