DHAKA: More than 500 people, including some opposition leaders, have been arrested in Dhaka over violence that has wracked Bangladesh and killed 163 people since students started protesting against civil service hiring rules, police said today.

What began as demonstrations against politicised admission quotas for sought-after government jobs has snowballed into some of the worst unrest of Prime Minister Sheikh Hasina's tenure.

A curfew has been imposed and soldiers are patrolling cities across the South Asian country, while a nationwide internet blackout since Thursday has drastically restricted the flow of information to the outside world.

"At least 532 people have been arrested over the violence" since the unrest began, Dhaka Metropolitan Police spokesman Faruk Hossain told AFP.

"They include some BNP leaders," he added, referring to the opposition Bangladesh National Party.

Bangladesh's top court yesterday pared back the hiring quotas for specific groups for government jobs, which are seen as secure and sought-after.

But the decision failed to mollify university student leaders, whose demonstrations against the quota scheme have sparked nationwide clashes that have killed 163 people, including several police officers, according to an AFP count of victims reported by police and hospitals.

A spokesman for Students Against Discrimination, the main group responsible for organising the protests, said: "We won't call off our protests until the government issues an order reflecting our demands."

Ali Riaz, a professor of politics and leading Bangladesh expert at Illinois State University, described the violence as "the worst massacre by any regime since independence".

"The atrocities committed in the past days show that the regime is entirely dependent on brute force and has no regard for the lives of the people.

"These indiscriminate killings cannot be washed by a court ruling or a government announcement."

Diplomats in Dhaka questioned Bangladeshi authorities' deadly response to the protests following a presentation by the foreign minister that blamed demonstrators for the violence, diplomatic officials said.

Foreign Minister Hasan Mahmud summoned ambassadors for a briefing yesterday and showed them a 15-minute video that sources said focused on damage caused by protesters.

But a senior diplomatic official in Dhaka, speaking on condition of anonymity, told AFP that United States ambassador Peter Haas said Mahmud was presenting a one-sided version of events.

"I am surprised you did not show the footage of police firing at unarmed protesters," the source quoted Haas as telling the minister.

A US embassy official speaking on condition of anonymity confirmed the ambassador's comments.

The diplomatic source added that Mahmud did not respond to a question from a United Nations representative about the alleged use of UN-marked armoured personnel carriers and helicopters to suppress the protests.

Bangladesh is a major contributor to UN peacekeeping operations around the world - earning significant revenues from its efforts - and has UN-marked equipment in its military inventories.

Government figures have repeatedly blamed the protesters and opposition for the violence.

Dhaka police spokesman Hossain said at least three policemen had been killed in the capital and about 1,000 injured, at least 60 of them critically.

The detainees included the BNP's third-most senior leader Amir Khosru Mahmud Chowdhury and its spokesman Ruhul Kabir Rizvi Ahmed, he said.

A former national football captain turned senior BNP figure, Aminul Huq, was also held, he added, as was Mia Golam Parwar, the general secretary of the country's largest Islamist party, Jamaat-e-Islami.

With around 18 million young people in Bangladesh out of work, according to government figures, the quota scheme's reintroduction deeply upset graduates facing an acute jobs crisis.

The Supreme Court decision curtailed the number of reserved jobs from 56 percent of all positions to seven per cent, most of which will still be set aside for the children and grandchildren of "freedom fighters" from Bangladesh's 1971 liberation war against Pakistan.

While the decision represented a substantial reduction to the contentious "freedom fighter" category, with 93 per cent of jobs to be awarded on merit, it fell short of protesters' demands to scrap it altogether.

The "freedom fighter" quota in particular is resented by young graduates, with critics saying it is used to stack public jobs with loyalists to Hasina's ruling Awami League.

Opponents accuse her government of bending the judiciary to its will.

Hasina, 76, has ruled the country since 2009 and won her fourth consecutive election in January after a vote without genuine opposition.

Her government is also accused by rights groups of misusing state institutions to entrench its hold on power and stamp out dissent, including by the extrajudicial killing of opposition activists.

Hasina inflamed tensions this month by likening protesters to the Bangladeshis who had collaborated with Pakistan during the country's independence war.

 - AFP