DHAKA, Bangladesh (CNN) -- Thousands of apparel workers clashed with police in Bangladesh, demanding higher pay on Monday, police and officials said.

The workers are demanding a minimum monthly pay of $104 revising the present $38 a month.

Police said violence mostly erupted in Gazipur and Savar, on the outskirts of capital Dhaka, where there are hundreds of apparel factories producing clothes for leading global brands from Europe and America.

The workers fought pitched battles with police and set fire to vehicles and part of some apparel factories in Gazipur, forcing the owners to shut down all factories in Gazipur district and its adjoining areas.

Several thousand workers also took to the streets in capital Dhaka, but they were dispersed by police and did not appear to commit any violence.

A cabinet minister Shahjahan Khan after a meeting with the factory owners and representatives of the workers called for calm and asked the workers to return to work.

Khan himself led a huge rally of the apparel workers in the capital on Saturday, demanding $104 as minimum monthly wage for the workers.

The recent unrest began Saturday when workers were denied leave from the factories to join Khan's rally.

Khan, however, at a news briefing on Monday said the unrest might be linked to outsider involvement, but did not give any details.

"Additional forces will be deployed to maintain law and order in the industrial districts," said Khan, also a transport labor leader.

The government recently constituted a wage board for fixing minimum wages for apparel workers, but the board was yet to come to a final decision, while the owners offered a 20% rise.

Bangladesh earns about $20 billion a year, 80% of the total export, by selling clothes to European and American brands.

In April 2013, over 1,100 people were killed when an eight-story apparel factory building caved in and collapsed in Savar.

In November 2012, a fire at an apparel factory in Savar killed 112 people.