A journalist working for the British newspaper Guardian is missing in Libya and has not been heard from since Sunday.

Ghaith Abdul-Ahad, a correspondent of Iraqi descent, was covering the savage fighting between rebels and pro-government forces in the town of Az Zawiyah, in western Libya.

In a statement, the Guardian said that urgent efforts are underway to establish the whereabouts of reporter Ghaith Abdul-Ahad who has been reporting from western Libya for the past two weeks. The Guardian has been in contact with Libyan government officials in Tripoli and London and requested them to act urgently to discover where he is, if he is safe and well, and to establish if he is in the custody of the authorities.

Abdul-Ahad was travelling with Andrei Netto, a Brazilian reporter, when he vanished. Netto was detained by Libyan security officials, but was later released on Thursday in good health and was in the care of Brazil's ambassador to Libya.

Netto’s newspaper, Estado de Sao Paulo, stated that Netto was arrested eight days ago and was held in the town of Sabratha, about 70 kilometers west of Tripoli.

However the whereabouts of Abdul-Ahad are unknown.

Abdul-Ahad has worked for the Guardian since and has spent long periods in such war-torn places as Somalia, Sudan, Iraq and Afghanistan.

Yesterday, there was outrage in Britain and elsewhere over the abusive treatment of three BBC reporters who were detained for 21 hours (and ultimately released) by Libyan government troops.

For them to be targeted, detained and treated with such cruelty, which could amount to torture, is completely unacceptable and in serious violation of international law, said Navi Pillay, the UN high commissioner for human rights

The BBC crew were also detained near Az Zawiyah.