Mogadishu, April 7 (IANS): Two foreign UN workers were shot dead in Somalia Monday by a gunman wearing a police uniform, police and witnesses said.

The two foreigners, whose nationalities were not yet known, worked with the UN Office on Drug and Crime (UNODC) and were at the airport in the Somalian town of Galkayo when the man in police uniform shot them, police officer Mohamed Ali told Xinhua.

"The gunman is now in detention and is being investigated. One of the white men died on the spot while the other was rushed to hospital where he was declared dead," Ali said.

Witnesses said the assailant shouted "Allahu Akbar", Arabic for Allah is great, when he started shooting at the victims.

The airport, where the incident occurred, is located in the northern part of Galkayo town controlled by the semi-autonomous region of Puntland.

The southern section of Galkayo is controlled by the Galmudug regional administration.

Al Shabaab militants have carried out intermittent attacks on both sides of the city but the radical group has not managed to establish a base in Galkayo.