Al-Shabab militants hold at least 20 hostage at Mogadishu restaurant after bombing

Dozens of people were being held hostage in the Somali capital on Wednesday evening, after a suicide car bomber targeted a popular restaurant, security officials said.

At least twenty civilians remained in the Pizza restaurant where al-Shabab militants are allegedly holding them at gunpoint, Reuters reported.

Meanwhile, at least six people were killed in the bombing, officials confirmed.

The suicide bomber drove a car loaded with explosives into the building," said Ali Mohamed, a police official, identifying the target as the Posh Treats restaurant. 

Security official Abukar Mohamed said there were "six people killed and several wounded" adding that the operation to clear the building was ongoing late on Wednesday night with security forces having cordoned off the area.

Witness Abas Ahmed, who was at another nearby restaurant when the explosion happened, described seeing "the dead bodies of several people and others who were injured."

Al-Shabaab, an al-Qaeda aligned militant group that launches regular suicide attacks in the capital against civilian, government and military targets, claimed responsibility for the bombing via its Radio Andalus broadcaster and said that its gunmen had afterwards stormed the restaurant compound.

Militant attacks often increase in tempo during Ramadan and Wednesday's bombing came in the evening after the breaking of the fast when mosques and restaurants are busy.

Posh Treats, a relatively new restaurant in an affluent part of the capital, is particularly popular with young and diaspora Somalis.

Al-Shabaab has been fighting for the last decade to overthrow successive internationally-backed governments in Mogadishu and has also launched attacks in Kenya and Uganda, both contributors to a 22,000-strong African Union force in the country.

Although pushed out of the capital in 2011 the group still controls parts of the countryside where a drought threatens to tip into famine this year.