Four UN aid workers have been kidnapped by suspected Al-Shabaab militants in southern Somalia, Xinhua news agency reported Wednesday, citing a local police source.

The four aid workers, all Somali nationals, were working on a polio vaccination program with the World Health Organization (WHO) when they were abducted early Tuesday in the town of Luuq in southern Gedo Province, Xinhua said. 

Negotiations were underway for their release, the police source added. There was immediate confirmation by the WHO. 

The Islamist militant group Al-Shabaab has been behind many attacks in Somalia and neighboring Kenya targeting humanitarian workers for political gains and monetary purposes.

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