Thousands of garment workers took to the streets of Bangladesh on Monday to protest a factory blaze that killed at least 110 people.

Demonstrators blocked a major highway and some threw stones at a factory nearby on the outskirts of the Bangladeshi capital, Dhaka.

Hundreds of workers were trapped in the fire that began late Saturday at the Tazreen Fashion factory outside Dhaka. Fire officials say a lack of emergency exits contributed to the deaths, with many workers jumping out of the multi-story building after being trapped in the blaze. Authorities are unsure what caused the fire.

The government has announced a national day of mourning for Tuesday.

Bangladesh has about 4,000 garment factories that make clothes for international brands. The country earns about $20 billion annually from overseas clothing sales, roughly 80 percent of its exports.

U.S. retailer Walmart issued a statement saying, “while we are trying to determine if the factory has a current relationship with Walmart or one of our suppliers, fire safety is a critically important area of Walmart's factory audit program and we have been working across the apparel industry to improve fire safety education and training in Bangladesh.”

A document posted on Tazreen Fashions' website said an audit conducted by an “ethical sourcing” assessor for Walmart gave the clothing manufacturer a “high-risk” safety rating. The website did not give details.

Work conditions at the country's garment factories are notoriously poor. Officials say at least 500 people have died in Bangladesh in garment factory accidents and fires since 2006. Activists say plant owners are rarely prosecuted for poor safety conditions.

On Monday, firefighters brought a new blaze at another garment factory outside Dhaka under control. Fire officials say there were no casualties at the 12-story building that contains several factories. The fire caused considerable damage to the building.