Gunmen have stormed a popular cafe in the diplomatic area of the Bangladeshi capital, Dhaka, taking a number of hostages, officials say.

Several foreigners are among those being held by eight or nine armed men in the Holey Artisan Bakery cafe in the city's Gulshan district, they add.

Two police officers have been killed in a gun battle, a spokesman said, and about 30 others injured.

So-called Islamic State (IS) has said it carried out the attack.

A statement on the group's self-styled news agency Amaq said militants had attacked a restaurant "frequented by foreigners". It said that more than 20 people "of different nationalities" had been killed but this has not been confirmed.

Security forces say they are trying to negotiate the hostages' release.

Initial reports said that as many as 20 foreigners were among those taken captive.

Seven Italian nationals are believed to be in the cafe, the Italian ambassador in Dhaka, Mario Palma, was later quoted as saying by Italian media.

A Japanese government spokesman said Tokyo was investigating reports that some of its citizens were among the hostages.

"We want to resolve this peacefully. We are trying to talk to the attackers," said Benazir Ahmed, chief of the Rapid Action Battalion, Bangladesh's elite police force.

"Our first priority is to save the lives of the people trapped inside."

Police said the gunmen burst into the Holey Artisan Bakery cafe at about 21:20 (13:20 GMT) and opened fire.