US freelance journalists Clare Morgana Gillis and James Wright Foley, respectively working for The Atlantic and GlobalPost, and Spanish photographer Manuel Varela de Seijas Brabo as well as South African photographer Anton Hammerl have been missing in Libya since Tuesday 05 April.

According to their colleagues and as reported by The New Yorker, they "were caught in the rapid-fire advance and retreat that has characterized the Libyan conflict thus far."

In a statement, the White House press secretary Jay Carney called for the journalists' release: "We call for the release of any journalists detained, any human rights activists, anyone detained unlawfully or inappropriately, and in this case, specifically with those journalists in mind, we call on and demand their release," he said.

According to The New Yorker, "the Qaddafi regime has said the four are being held by military authorities, and has promised that they will be freed in due course."

The SA National Editors' Forum and the Professional Journalists' Association of South Africa have also called on the Libyan government to release Hammerl and other journalists captured by Libyan forces during the current unrest. "Both parties expressed dismay that [South Africa's] President Zuma failed to raise the issue of these detentions with Gaddafi, when he headed an African Union delegation this week to Libya."

The South African government has since asked the US for help in its efforts to find Hammerl.

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