Britain's Guardian newspaper said on Thursday it was making urgent attempts to trace one of its correspondents who has gone missing in Libya where he has been covering the recent unrest.
Ghaith Abdul-Ahad, an Iraqi national, who had been reporting from western Libya for the last two weeks, had not been in contact with the paper since Sunday, the Guardian said on its website.
The paper said Abdul-Ahad, who has worked for it since 2004 and has previously worked in Iraq and Afghanistan, had been travelling with Andrei Netto from Brazilian newspaper Estado, who was also missing.
They were on the outskirts of Zawiyah, a rebel-held town about 50 km (30 miles) west of the capital Tripoli and the scene of fierce fighting in recent days between insurgents and forces loyal to Muammar Gaddafi.
"The Guardian has been in contact with Libyan government officials in Tripoli and London and asked them to urgently give all assistance in the search for Abdul-Ahad and to establish if he is in the custody of the authorities," the paper said. On Wednesday, the BBC said one of its teams was detained by Libyan security forces, beaten and subjected to mock execution after they were arrested at a checkpoint while on the way to Zawiyah.
The trio were accused of spying and had their lives threatened during the 21 hours they were held by soldiers and secret police loyal to Libyan leader Muammar Gaddafi, it said.
The Libyan government has restricted the movements of foreign journalists based in Tripoli and says they must only travel with official escorts.