Islamic militants have stormed a hotel in Somalia’s capital, engaging in an hours-long exchange of fire with the security forces that left at least 20 people dead, according to police and witnesses.

In addition, at least 40 people were wounded in the late Friday night attack – and security forces rescued many others, including children, from the scene at Mogadishu’s popular Hayat Hotel, they said on Saturday.

The attack started with explosions outside the hotel before the gunmen entered the building.

Somali forces were still trying to end the siege of the hotel almost 24 hours after the attack started.

Gunfire could still be heard on Saturday evening as security forces tried to contain the last gunmen thought to be holed up on the hotel’s top floor.

The Islamic extremist group al-Shabab, which has ties with al Qaida, claimed responsibility for the attack, the latest of its frequent attempts to strike places visited by government officials.

The attack on the hotel is the first major terror incident in Mogadishu since Somalia’s new leader, Hassan Sheikh Mohamud, took over in May.

In a Twitter post, the US Embassy in Somalia said it “strongly condemns” the attack on the Hayat.

“We extend condolences to the families of loved ones killed, wish a full recovery to the injured, & pledge continued support for #Somalia to hold murderers accountable & build when others destroy,” it said.

There was no immediate word on the identities of the victims, but many are believed to be civilians.