Ready-made garments (RMG) workers from several factories in Ashulia, Savar, staged protests on Thursday.
The demonstrations began in the morning, with workers along different points of the Baipail-Abdullahpur road taking part.
Attacks were reported at several factories in Ashulia, including Ha-Meem, Medlar Apparels Limited, and Trouser Line Limited, as well as at factories belonging to the Nasa Group since morning.
By noon, at least three factories in Ashulia had declared a holiday due to the attacks.
Police have detained two individuals in connection with the attacks.
Meanwhile, it has been reported that officers and members of the industrial police were injured by brickbats thrown by the workers. Their identities could not be known yet.
Bonny Amin Sorkar, an official at Medlar Apparels Limited, said the factory was closed after some youths threw bricks and broke CCTV cameras around 8:30am on Thursday.
Around 11:30am, workers from Pearl Garment Company Limited blocked the Nabinnagar-Chandragam highway in the Polash Bari area, demanding an increase in allowance, attendance bonus, and other issues.
During the worker protests, it was reported that 20-30 people were injured and were taken to the Ashulia Women and Children Hospital.
Dr Mirazul Islam, a residential physician at Ashulia Women and Children Hospital, said that around 300 patients had come to the hospital. Their conditions are stable, and those with head injuries are under observation.
Superintendent of Police Mohammad Sarwar Alam of Industrial Police-1 said that most factories in Ashulia began work at the scheduled times on Thursday.
Al-Muslim and New Age factories are closed. Ananta Garments has not started work yet due to unresolved internal issues. Action is being taken against those trying to create instability, he added.
He also mentioned that the Industrial Police, the army, and the Border Guard Bangladesh (BGB) are trying to maintain order and keep the garment factories operational to avoid any untoward situations.