MOGADISHU, June 15 (Xinhua) -- Gunmen attacked two restaurants in Somalia's capital of Mogadishu on Wednesday night, killing at least 17 people and injuring 26 others, with an unknown number of hostages being held by the attackers, rescuers said.

An emergency team Aamin Ambulance said Thursday on Twitter that it has found 17 bodies and evacuated 26 people who were wounded, but has to "stop rescue work as the area became too dark while bombings are still going on."

An earlier report quoting police officer Mohamed Nur said eight people were killed in the attacks.

A suicide bomber drove a car loaded with explosives into the Posh restaurant in Hodan district and detonated it, Nur told Xinhua.

A group of gunmen then bombed the Pizza House, a restaurant near Posh, and clashed with security personnel, he added.8 The two restaurants are frequented by government officials and young people.

A witness said the explosion was huge and could be felt from a distance.

"We heard a huge explosion which hit Pizza House and Posh House. We understand some people have been killed," Abdullah Yasin told Xinhua.

Heavy gunfire could be heard inside the Pizza House where an unknown number of hostages were held, police said.

Somalia-based al-Shabaab has claimed responsibility. The al-Qaida-affiliated group has launched frequent attacks on targets including civilians and government institutions in the Horn of Africa country since the militants were forced out of Mogadishu by African Union (AU) troops in 2011.

Somali President Mohamed Abdullah Mohamed in April declared war against the extremists, offering amnesty to militants who surrendered within 60 days and warning the rest would "face the consequences."

Somalia's special forces destroyed a key al-Shabaab command and supply hub on Sunday in the country's southern regions.

"We have long suffered at the hands of Al-Shabaab which is supported by global terror networks. We and our international partners will take every possible precaution to protect our civilian population from harm during these operations while targeting terrorists," the president said Sunday.

The U.S. military also confirmed its special forces killed eight al-Shabaab fighters in an airstrike conducted in southern Somalia on Sunday.

In a statement issued on Sunday night, the U.S. Africa Command (Africom) vowed to intensify attacks against al-Shabaab militants in order to protect people, saying the militants have taken advantage of the safe haven to kill and maim people.

According to Africom, al-Shabaab has overrun three bases of the African Union Mission to Somalia, a peacekeeping mission operated by the AU, by amassing large numbers of fighters and attacking in overwhelming numbers in the last eight months.

It said al-Shabaab has also increased its combat capability by seizing heavy weaponry, armored vehicles, explosives, small arms, ammunition, and other miscellaneous supplies.

The terrorist group has cemented its control in southern and central Somalia and has used this area to plot and direct terror attacks, steal humanitarian aid, and to shelter other radical terrorists.