Twenty hostages have been killed during a siege in a cafe in the Bangladesh capital Dhaka.

At least six militants were also killed and 13 hostages rescued after Bangladeshi security forces stormed the restaurant popular with foreigners to end a 10-hour stand-off.

Gunmen stormed the Holey Artisan Bakery in Dhaka's Gulshan area, a diplomatic zone, on Friday night.

A Japanese government spokesman said that a Japanese hostage was rescued with a gunshot wound but seven others are unaccounted for. Deputy chief cabinet secretary Koichi Hagiuda said that the eight were together at the restaurant during the attack.