A national officer working for the UN Development Programme (UNDP) in Mogadishu was kidnapped by gunmen in the city on Sunday, the UN announced on Monday.

In a statement, the office of the UN Humanitarian Coordinator for Somalia confirmed that the employee, Professor Muhammad Ali Aborkor, was abducted on Sunday by "persons unknown in the vicinity of K4 [in southern Mogadishu]".

The statement said the UN Country Team for Somalia was working to establish contact with the kidnappers "in order to ascertain his condition and whereabouts, and to ensure his safe release".

Humanitarian sources in Mogadishu told IRIN Aborkor was travelling on a bus on his way to his house in the Medina district of southwest Mogadishu, "when gunmen who were riding in the same bus kidnapped him at around 4:30 p.m. local time". It is unclear why Aborkor was kidnapped, where he is being held and by whom. "We have no idea where he has been taken to," the source said.

Mogadishu police chief, Abdi Hasan Awale Qeybdid, told IRIN the police were investigating the case. Qeybdid said the police had some leads, but declined further comment.

In another development, a former UN security guard, accompanied by his gunmen, blockaded the UNDP compound in Mogadishu for about three hours on Monday, stopping anyone from entering or leaving. According to Qeybdid, the man was insisting that he had not been fully compensated for his services to the UN.

The incident, which started at around 11:00 a.m., was over by about 2:30 p.m. Qeybdid told IRIN that elders from the man's clan succeeded in peacefully removing the man and his gunmen. "There is no one blockading the compound now," Qeybdid added.