Concerns grow over the fate of missing photographer Anton Hammerl as two journalists captured with him in Libya last month say they have no idea where he is.

The 41-year-old British-based photographer is believed to have been seized by Gaddafi loyalists near the oil town of Brega on 5 April.

Speaking through an intermediary, US journalists James Foley and Clare Gillis told news website Global Post that they were being treated well.

The pair are now being held in Tripoli, along with Spanish photographer Manu Brabo who was captured at the same time.

?The intermediary said Gillis and Foley reported that Brabo was also in the same detention facility, but that they did not know the whereabouts of Hammerl,? reported Global Post.

Reacting to the news, Anton?s wife Penny once again pleaded for his release.

She said yesterday: ?It is with great concern that 37 days have passed with us having absolutely no contact with Anton.?

Anton holds South African and Austrian citizenship and lives in Surbiton, Surrey.

Penny added: ?He has not been allowed consular access. All we have, via the South African and Austrian governments ? who themselves have received third-party assurances ? is the word of the Libyans that they are detaining him.?

Last week, a candle-lit vigil for Anton was held in central London.