, AP
Bangladeshi policemen clear out an area to facilitate action against heavily armed militants who struck at the heart of Bangladesh's diplomatic zone on Friday night, taking dozens of hostages at a restaurant popular with foreigners, Dhaka, Bangladesh, Saturday, July 2, 2016. Police sustained casualties and dozens of people were wounded in a gun battle as security forces cordoned off the area and sought to end the standoff. (AP Photo)

DHAKA, Bangladesh (AP) — Bangladesh forces stormed a restaurant where heavily armed militants held dozens of people hostage for 10 hours Saturday morning, triggering explosions and finding at least five bodies lying in pools of blood. Japan's government said that 12 people were rescued.

The Islamic State group claimed responsibility for the attack on the Holey Artisan Bakery in Dhaka's Gulshan area, according to the SITE Intelligence Group, which monitors jihadis activity online. At least 35 people, including about 20 foreigners, were trapped inside the restaurant, said kitchen staffer Sumon Reza, who was among more than 10 people who managed to run to the rooftop and escape when the militants moved in Friday night.

With the sound of gunfire and explosions, local TV stations reported that the rescue operation began at 7:40 a.m. It included army personnel with automatic weapons and at least seven armored vehicles. Several ambulances were on standby.

Local media reported that an Argentine and two Bangladeshis were rescued from the restaurant early Saturday, but details about their condition were not immediately available.

Commandos storming the restaurant discovered five bodies lying in blood, a police official who was not identified told Channel 24 TV station.

In Tokyo, Deputy Chief Cabinet Secretary Koichi Hagiuda said that 12 people were rescued in the raid, including two foreigners, but he couldn't say if they were Japanese. His information was based on Dhaka police.

A news agency affiliated with the Islamic Group claimed that 24 people had been killed and 40 wounded, including foreigners, according to SITE. The figures could not be independently confirmed.

The Amaq news agency also posted photos purportedly showing the bodies of hostages. The authenticity of the pictures could not be confirmed either.

The attack marks an escalation in the growing drumbeat of militant violence to hit the traditionally moderate Muslim-majority nation in the past three years, but with increasing frequency in recent months. Most attacks have been by machete-wielding men singling out individual activists, foreigners and religious minorities.

Bangladesh did not immediately respond to the claim of responsibility by IS, but in the past have denied that the extremist group has a presence in the country. The U.S. State Department said it had seen the IS claim, but could not confirm its authenticity.

Associated Press writers Katy Daigle in New Delhi, Matthew Pennington in Washington and Ken Moritsugu in Tokyo contributed to this report.