April 20, 2011 -- Award-winning war photographers Tim Hetherington and Chris Hondros were killed in an attack on the besieged Libyan city of Misrata, sources close to both men confirmed late today.

"It is with great sadness we learned that our son and brother, photographer and filmmaker Tim Hetherington, was killed today in Misrata, Libya, by a rocket-propelled grenade," the Hetherington family wrote on Facebook.

Getty Images confirmed in a statement that Hondros, one of its staff photographers, also died from injuries sustained in the attack.

"Chris never shied away from the front line, having covered the world's major conflicts throughout his distinguished career, and his work in Libya was no exception," the company said. "He will be sorely missed."

News of the deaths first surfaced on Twitter and on the Facebook page of Andre Liohn, a French photographer who was apparently with Hetherington and Hondros at a Libyan hospital.

Hetherington, one of the best known photojournalists and winner of the prestigious Dupont Award, produced powerful pieces for ABC News' "Nightline" from the Korengal Valley, Afghanistan, and directed the documentary "Restrepo," which was nominated for an Academy Award.

He was in Libya to "continue his ongoing multimedia project to highlight humanitarian issues during time of war and conflict," his family said.

Hondros has covered conflicts from Kosovo to Lebanon, Iraq to Afghanistan and many more. His work has appeared in virtually all the major American papers and magazines, and his awards include the Robert Capa Gold Medal, war photography's highest honor.

Three other journalists were believed to be wounded in the same attack, including Michael Brown. The identity of the other two have not yet been confirmed.

"Tim was one of the bravest photographers and filmmakers I have ever met," said ABC News' James Goldston, who worked closely with Hetherington as executive producer of "Nightline."

"During his shooting for the 'Nightline' specials, he very seriously broke his leg on a night march out of a very isolated forward operating base that was under attack," Goldston said. "He had the strength and character to walk for four hours through the night on his shattered ankle without complaint and under fire, enabling that whole team to reach safety."

Hetherington was embedded with the Army unit in Afghanistan when Army Staff Sgt. Salvatore Giunta put his life on the line to save his comrades. Giunta later became the first living recipient of the Medal of Honor since Vietnam.

Army Maj. Dan Kearney, who was in charge of the platoon to which Hetherington was attached, told ABC News from Afghanistan that Hetherington was a "brother" whose documentary work was applauded by "more than a million soldiers who were there for him and cheering for him."

"The thing about the wars in Afghanistan, they've been known as the ghost wars, you know, because not often does one really see the enemy," Hetherington said of the battle in an interview with ABC News last year.

"You're fighting sometimes at distance, but they're very elusive, the insurgents, and on the night of the 25th of October ... Sal Giunta finally came face to face with them. And when he did, it was because they were dragging off his friend Joshua Brennan," Hetherington said.

"It was pretty, pretty, pretty traumatic events for me," he said.

White House press secretary Jay Carney said the Obama administration was "saddened" to learn of Hetherington's death and remains "deeply concerned about the well being of other journalists who were wounded alongside him."

ABC News' Martha Raddatz, Nicholas Schifrin and Kristina Wong contributed to this report.