2 journalists are first American deaths in Libya

Tim Hetherington, best known for co-directing the Oscar-nominated documentary on the Afghanistan war "Restrepo," was killed in Libya on Wednesday while covering the conflict as a photojournalist for Panos Pictures, according to one of his other employers, Vanity Fair magazine.

Along with Hetherington, the New York Times reports that Chris Hondros, a photojournalist with Getty Images, died later from his wounds sustained in the same rocket-propelled grenade attack.

Also wounded in the incident were two other journalists: Guy Martin, working for Panos also; and Michael Christopher Brown , who has worked as a freelancer for several large publications.

Hetherington, who held dual U.S.-U.K. citizenship, and Hondros were veteran war photographers who had seen heavy fighting in several other conflicts.

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Misrata has been under siege for nearly two months, and human rights groups have warned the situation there is increasingly dire, as it is one of the last rebel-held cities in Western Libya.

The photographers got to the heavily contested city by sea from Benghazi, the rebel capital, according to the Times. The group had allegedly been working together near the front lines when they were struck by a rocket-propelled grenade.

Exchanges of fire were heard Wednesday between Libyan troops and armed residents in the city center, the Associated Press reports. NATO planes flew overhead, but did not carry out airstrikes.

Rebel fighters said government snipers have been shooting from rooftops.

While Hetherington is more widely known for his documentary film on the Afghanistan war, he is well-renowned in photojournalism circles. In 2007, he won the prestigious World Press Photo of the Year award for his work in Afghanistan.