At least three people were killed and several wounded in twin attacks at a restaurant on the popular beachfront of Somalia's capital Mogadishu, witnesses and police said Friday.

The blasts, the latest in a string of attacks in the war-ravaged city, were reportedly caused by a suicide attacker wearing a vest packed with explosives, followed by a car bomb.

Somalia's president has offered an amnesty to young pirates in a bid to end attacks off the Horn of Africa nation's coast as he seeks to rebuild the war-torn country, he told Agence France Presse.

"We have been negotiating with the pirates indirectly through the elders," said President Hassan Sheikh Mohamud. "Piracy has to end."

A U.S. court on Wednesday convicted five Somali men of piracy over a 2010 attack on a U.S. naval ship in the corsair-infested waters off the Horn of Africa.

The five men were on a skiff that fired an AK-47 at the USS Ashland, a dock-landing vessel, which fired back with a 25mm machine gun, setting the pirates' ship on fire and killing one of its crew members.

Somalia's al-Qaida-linked Shebab on Wednesday issued a stark warning to Kenyan voters ahead of next week's general elections, threatening them with a "long, gruesome war".

The Islamist group argued Kenya was safer when it ruled bordering southern Somalia but stopped short of saying who Kenyan voters should choose in the March 4 polls.

Somali government troops and African Union forces seized the formerly Islamist-held town of Burhakaba on Wednesday, the latest loss for the al-Qaida linked Shebab fighters, commanders said.

Soldiers backed by tanks stormed the town from three directions but the hardline Shebab had already fled before the assault, said Somalia's deputy army commander Abdikarin Yusuf Dhegobadan.

Somalia accredited ambassadors from five European nations Tuesday, a move hailed by the president as sending a signal that the war-ravaged nation was "becoming a normal country."

Ambassadors of Belgium, France, Germany, Spain and Finland presented their credentials to Somali President Hassan Sheikh Mohamud, who said he hoped Somalia would "soon see many international flags flying over Mogadishu".

Clashes between rival Somali clan militias in Kismayo killed 11 Saturday, witnesses said, in the worst unrest since Kenya-backed pro-government forces recaptured the southern port from Islamist insurgents last year.

The fighting erupted when a clan leader died at a police station, prompting pitched battles between Marehan and Ogadeni clansmen, two of the three groups that have traditionally fought for control of Kismayo.

Somalia's Shebab insurgents claim to have executed a captured Kenyan soldier and repeated threats to kill five other hostages, the extremists said Friday.

"While the mujahedeen have executed the serving KDF (Kenya Defence Force) soldier, there is still a chance of securing the release of the remaining five prisoners," the Shebab said in a statement.

At least four people were killed Monday when a suicide bomber blew himself up in his car in an attack aimed at a senior police officer in Somalia's central Galkayo region, police said.

"There are at least five people dead, including the bomber," said Mohamed Abdullahi, a police officer in the town, which straddles the border between the northern breakaway state of Puntland and the self-proclaimed region of Galmudug.

Somalia's al-Qaida linked Shebab insurgents have returned to Twitter with a new account, less than two weeks since they were suspended after posting photographs of a French commando they had killed.

"For what it’s worth, shooting the messenger and suppressing the truth by silencing your opponents isn’t quite the way to win the war of ideas," read one of the messages on the new account, which opened late Sunday.