A massive firefight has broken out between police and an unknown number of gunmen in a restaurant in Dhaka's diplomatic zone, police said Friday night, with reports that some people may have been taken hostage.

"Unknown number of people are still inside but we cannot confirm whether they are held hostage," Gulshan area police officer Sayedur Rahman told AFP.

Two police officers were seriously injured in the gunfight, private television station Channel 24 said.

According to the online edition of the Daily Star newspaper, about five assailants entered Holey Artisan Bakery restaurant on Road 79 in the upmarket Gulshan area and opened fire at around 9:20pm (1320 GMT).

The incident took place near the Nordic Club, where expatriates of Nordic nations gather, and the Qatar embassy.

Bangladesh has been reeling from a wave of murders of religious minorities and secular activists by suspected Islamist militants.

Earlier Friday a Hindu temple worker was hacked to death in western Bangladesh.