Thousands of Bangladeshi protesters have crowded into a central Dhaka square for mass protests, demanding Prime Minister Sheikh Hasina resign following a deadly police crackdown.

Asif Mahmud, one of the key protest leaders in a nationwide civil disobedience campaign, asked supporters to be ready to fight. “Prepare bamboo sticks and liberate Bangladesh,” he wrote on Facebook on Sunday.

While the army stepped in to help restore order in the wake of earlier protests, some former military officers have since joined the student movement, and ex-army chief General Iqbal Karim Bhuiyan turned his Facebook profile picture red in a show of support.

Army chief Waker-uz-Zaman spoke to officers at the military headquarters in Dhaka on Saturday, telling them the “Bangladesh Army is the symbol of trust of the people”.

“It always stood by the people and will do so for the sake of people and in any need of the state,” he said, according to an army statement issued late on Saturday. The statement did not give further details and did not explicitly say whether the army backed the protests.

The demonstrations began in early July over the reintroduction of the quota scheme, which reserved more than half of all government jobs for certain groups. It has since been scaled back by Bangladesh’s top court.

Rallies against the quotas led to days of mayhem that saw more than 200 people killed in some of the worst periods of unrest during Hasina’s 15-year tenure.

Troops briefly restored order but crowds returned to the streets in huge numbers this week in an all-out noncooperation movement aimed at paralysing the government.

On Saturday, when hundreds of thousands marched in Dhaka, the police were largely bystanders watching the protest rallies, which have grown into a wider antigovernment movement across the South Asian nation of some 170 million people.

Students Against Discrimination, the main group behind the protests, has asked people to stop paying taxes and utility bills from Sunday to pile pressure on the government. They have also asked government workers and labourers in the country’s economically vital garment factories to strike.

Hasina, 76, has ruled Bangladesh since 2009 and won her fourth consecutive election in January after a vote without genuine opposition. Her government is accused by rights groups of misusing state institutions to entrench its hold on power and stamp out dissent, including through the extrajudicial killing of opposition activists.