Suspected members of al-Shebab sit on a truck after being rounded up by Somali troops at Elasha Biyaha, Somalia in June 2012. Supporters of Somalia's Al-Qaeda linked Shebab killed 14 people and wounded 20 more in a double suicide attack in the capital Mogadishu Thursday, in one of most deadly attacks for several months

Supporters of Somalia's Al-Qaeda linked Shebab killed 14 people and wounded 20 more in a double suicide attack in the capital Mogadishu Thursday, in one of most deadly attacks for months.

"One bomber detonated himself in the restaurant, then another blew himself up just outside, killing 14," said security official Mohamed Dahir Abdulle.

The attack, the latest in the war-ravaged city where the hardline Shebab have vowed to topple the government, was one of the first to target several new upmarket restaurants recently set up by the Somali diaspora.

"There are 14 people killed by two misguided criminals," the state-run Radio Mogadishu said in a broadcast, adding that around 20 more were badly wounded in the blast.

Those killed included three Somali journalists, with at least four others wounded, press rights watchdog Reporters Without Borders (RSF) said.

While there was no indication that journalists had been a specific target, RSF said the restaurant was well known as a popular place for the media.

The deaths take the number of journalists killed this year in Somalia to 12, surpassing 2009 when nine died as the "deadliest year" on record, it said.

"There were many wounded, many of them with severe wounds," said Hassan Ibrahim Abdullahi, who was in the restaurant at the time.

Shebab spokesman Ali Mohamud Rage told AFP the bombing was carried out by the group's supporters.

"Action has been taken by sympathisers of the Shebab, who were angry with the situation in Somalia, especially the intervention by foreign troops," he said.

"We did not directly order the attacks, but there are lots of angry people in Somalia who support our fight and want to change the situation."

Ali Mohammed Yassin, another diner in the restaurant, described a "loud explosion" and said that badly wounded victims were rushed to hospital who he feared "would not survive".

The bombers targeted the popular Village restaurant, run by Somalis who had returned to their country from Britain, an eatery popular with influential Somalis as well as the few foreigners living in the city.

The restaurant is opposite the National Theatre, and about a kilometre (half a mile) from the presidential palace.

Often hailed as a symbol of revival for Mogadishu, it was set up following the Shebab's pullout of fixed positions in the city last year.

After over two decades of anarchy and war, the seaside city has seen modest improvements since the Shebab left frontline fighting positions, with a boom in building and businesses.

However, the hardline fighters switched to guerrilla attacks in Mogadishu -- including suicide bombings -- and remain a potent threat.

Last week they launched a failed assassination bid against the newly elected president, killing three soldiers.

The attack comes as the Shebab face growing pressure on the last major city they hold -- the southern port of Kismayo -- which Kenyan troops with the African Union force alongside Somali militia gunmen are battling towards.

The key Shebab-held towns of Afgoye, Baidoa and the port of Marka have all fallen in recent months, with the militants largely retreating ahead of assault.

While the insurgents have continued to carry out attacks in Mogadishu including grenade attacks, the last blast on the scale of Thursday's attack was in February, when a suicide bomber killed 15 at a cafe.