Mogadishu, Somalia (CNN) -- At least 14 people died and 15 others were wounded in an attack on the U.N. headquarters in the Somali capital of Mogadishu on Wednesday.

Seven militants, four U.N. employees and three female civilians were killed, said Abdikarim Hussein Guled, the country's interior and national security minister. The other victims were rushed to a hospital.

Al-Shabaab, the militant group linked to al Qaeda, claimed responsibility, the group said on Twitter.

Prime Minister Abdi Farah Shirdon deplored the "senseless and despicable" assault against an agency that has been a friend and partner.

"I and all Somalis are appalled that they should be the target and victims of such barbaric violence," Shirdon said.

It was the latest in a series of attacks in the city, the heart of an unstable nation beset with civil strife, with government and African Union forces battling Islamic militants for years in an effort to bring stability to the land.

Last month, a suicide bomber targeted a Qatari delegation, killing at least eight people. Al-Shabaab also claimed responsibility for that strike.

In April, militants forced their way into a court building in Mogadishu and killed 29 people, including members of Al-Shabaab, sources said.

Police Officer Hussein Ahmed said that in Wednesday's violence, one attacker blew himself up at the entrance of the U.N. compound, which is near the city's airport.

Others wearing suicide vests entered the U.N. compound. He said Somali and AU forces surrounded the building and fought with the armed assailants.

The attack devastated the area. Mangled buses and cars sat in disfigured heaps, the windows of nearby apartments shattered, the ground littered with blood and body parts.

A large brown plume of smoke was visible in the air as ambulances rushed to the scene and carried away the wounded.

The compound has now been secured and is in the hands of AU troops, the official Twitter account of the African Union Mission to Somalia said. Shirdon also assured city residents that the government remains in control of security and underscored the swift action by the forces against the attackers.

"All our thoughts and prayers are with our U.N. colleagues today," Shirdon said. "Al-Shabaab will not derail the peace process. They will not stop our recovery. Violence will not win."