Around 5,000 workers of at least 25 factories started demonstrations on Dhaka-Tangail highway around 9:00am, said Abdus Sattar, deputy assistant director of industrial police.
On information, police rushed to the spot and resisted the agitating workers from blocking the busy highway during the rush hours.
In face of police resistance, the marauding workers vandalised two human haulers and hurled brick chips at the factory buildings situated beside the highway.
To take the situation under control, law enforcers charged batons and fired several rubber bullets, lobbed teargas canisters to disperse them, leaving at least 20 workers injured, the police official said.
The injured people took primary treatment from the local clinics.
Fearing vandalism, the authorities suspended their production at 25 factories including Envoy, The Rose Limited and DK Garments located at Jamgora, Shimultola, Gorat, Saker Market and Narshingpur of Ashulia.
There are total 350 garments factories in the areas, said Abdus Sattar, deputy assistant director of industrial police.