By Ibrahim Mohamed
MOGADISHU (Reuters) - Four U.N. humanitarian workers kidnapped on Monday by gunmen in southern Somalia have been freed, hardline Islamist insurgents and the United Nations said.
"I can confirm to you that all four aid workers were released from militia who abducted them in Wajid this morning -- unconditionally after a joint effort," al Shabaab spokesman Sheikh Muktar Robow Mansoor told Reuters.
The United Nations said a small, independently operating group had seized a Somali national working in Wajid and three foreign staff members en route to Kenya from the semi-autonomous northern Somali region of Puntland.
"I am very enormously relieved that our staff are free and safe," said U.N. Resident and Humanitarian Coordinator Mark Bowden in a statement from Nairobi.
"The United Nations is very grateful for the efforts and intervention of the local authorities who used their influence and reach to ensure our dedicated staff was cared for and ultimately released safely and quickly," he said.
Somalia is one of the most dangerous countries in the world for aid workers, who have been the targets of assassinations and kidnappings during a two-year insurgency led by Islamist insurgents against the government and foreign backers.
The U.N.'s World Food Programme has continued to deliver food aid in areas of Somalia controlled by al Shabaab, which is on Washington's list of foreign terrorist groups.
"This is an important affirmation that the U.N. presence and its activities in Bakool and the surrounding areas is accepted and protected by the local communities and leaders," said Bowden.
"The quick and positive resolution of this incident will ensure the aid operation can go on unhindered," he said.
With kidnaps in Somalia, captives are usually well treated and set free once a ransom is paid.
After more than two years of fighting, more than a million Somalis have been uprooted from their homes and a third of the population depends on food aid.
President Sheikh Sharif Ahmed, a moderate Islamist elected earlier this year in the 15th attempt to form a central government, is struggling to deal with various insurgent groups who control swathes of territory.
On Monday, an unknown man threw a hand grenade into the United Nations Development Programme compound in Mogadishu, injuring a guard, police said.
(Editing by David Clarke and Giles Elgood)