(CNN) -- Flesh and blood covered the ground near Somalia's presidential palace Wednesday after a suicide bomber detonated his explosive belt, killing two people and wounding four, a law enforcement official said.
Col. Abdullahi Hassan Barise, the head of the country's criminal investigation department, told reporters at a news conference the bomber also died.
"In initial assessment, I can confirm that those killed in the suicide attack are two civilians and the bomber himself and all the four wounded are also civilians,'' Barise said.
The attacker blew himself up at a tea shop near the presidential palace, Barise said, adding that an investigation is under way.
Al-Shabaab, a militant Islamist group fighting Somalia's weak transitional government, claimed the responsibility for the attack.
Radio Alfurqan, the group's radio station, broadcast an announcement that one of their suicide bombers infiltrated the area near the presidential palace and carried out the bombing.
Al-Shabaab, which recently announced it has officially joined the family of organizations under the al Qaeda banner, controls much of southern Somalia and is active around the capital, Mogadishu. The United States considers Al-Shabaab a terrorist group.