War photographers Chris Hondros and Tim Hetherington were killed last week while covering the fight between pro-Gaddafi forces and rebels for control of the Libyan city of Misrata. Two other journalists, Guy Martin, a Briton working for the photo agency Panos, and Michael Christopher Brown, a photojournalist for Corbis, were both seriously injured by the same mortar fire. IFEX members paid tribute to the journalists, and are regularly updating news on the free expression situation in Libya.

Hetherington won several distinguished prizes, including the World Press Photo Award in 2007, for his work covering conflicts over the last decade. He also co-directed "Restrepo", an Oscar-nominated documentary about United States soldiers fighting in Afghanistan.

Human Rights Watch worked with Hetherington on a number of human rights stories over the years, including assignments to Darfur, Chad and Sri Lanka. "Tim Hetherington was much more than a war reporter," said Kenneth Roth, executive director of Human Rights Watch in a tribute to him. "He had an extraordinary talent for documenting, in compassionate and beautiful imagery, the human stories behind the headlines."

"This is a devastating loss to many of us personally," said Roth. "But it is also a devastating loss to the human rights community. His work has raised the visibility of many of the world's forgotten conflicts. The legacy of his exceptional photographs will serve to inspire those following in his footsteps."

See them here.

(Human Rights Watch is also offering video clips of Hetherington's work on its site. )

Nic Bothma via CPJ

Hondros was an award-winning photographer for Getty and had covered Iraq, the West Bank, Sierra Leone, Kosovo and Afghanistan. He was nominated for a Pulitzer Prize in 2004 for his work in Liberia, and won the Overseas Press Club of America's Robert Capa Gold Medal for his "exceptional courage and initiative" in Iraq.

But the people in his pictures were more than subjects, says Nic Bothma, the West Africa chief photographer for European Pressphoto Agency and a friend of Hondros's, in a tribute posted by the Committee to Protect Journalists (CPJ). After the war in Liberia ended, he found the militia commander who was the subject of one his more celebrated photos, enrolled him in school and paid for his tuition.

View a slideshow of some of Hondros's images from some of the world's most treacherous spots on CPJ's blog.

Two other journalists have been killed this year in the Libyan conflict. Mohammed al-Nabbous, founder of the online Libya Al-Hurra TV, was killed as he was streaming live audio from a battle in Benghazi on 19 March. Cameraman Ali Hassan al-Jaber was shot when his Al Jazeera crew was ambushed near Benghazi on 13 March.

CPJ has documented more than 80 attacks on the press since political unrest erupted in Libya in February. At least six local journalists are missing amid speculation they are in the custody of security forces. One international journalist and two media support workers are also unaccounted for.

Click here for CPJ's running list of violations.