Peter van Agtmael is used to the battlefield. Since 2006, he has regularly covered the wars in Iraq and Afghanistan. Last Friday, watching the protests in Egypt intensify, he packed his bag and boarded the first plane for Cairo.

"Sunday, the first night I spent in the square was quite dramatic, with protestors sitting in front of tanks to keep them from moving into the crowd," he emails BJP. "The following days were quite calm. A series of peaceful rallies without aggression and a lot of excitement and expectation. Everything went south on Wednesday."

Van Agtmael usually went to the different protests with other photographers - Michael Appleton, Dominic Nahr, Ivor Prickett, Guy Martin and Ed Ou. "But we'd quickly become separated in the crowd," he explains. "We stayed in touch via cellphone. The situation was so vast that there was no real focus to my images. Mostly I tried to isolate moments that tried to show the emotion and grand scale of the event."

And, he says, the anti-government protestors were "incredibly accommodating to us. They want their story out." But this morning, things didn't go as planned for the Magnum photographer.

"In the morning I was at a pro-Mubarak rally that was largely peaceful, though more aggressive than the anti-Mubarak rallies," he tells BJP. "As the rally waned I headed back to the square. On the way I ran into Andrew Henderson, another photographer. "We decided to try to get into the square, but there was a vast crown of pro-Mubarak protestors starting a fight. We took out our cameras to take pictures and immediately we were surrounded by yelling Mubarak supporters."

He continues: "We began to leave the square at a walk but were followed. I was in front and Andrew was behind me. They started attacking him and he yelled 'run.' We both started sprinting but were set upon on all sides. I ran zig-zags but people kept coming, wrenching my cameras from my arms and kicking and punching at me."

"The crowd closed in and I was hit with a sharp object on the head and went down," he says. "I started getting kicked and punched, and curled into a ball. After what must have been a few seconds some people forced their way through and surrounded me, picking me up and shielding me from most of the blows of the other Mubarak supporters. They carried me to the army a few hundred feet away who put me in a compound. As I lay on the ground dazed and bloodied I could hear them yelling and pounding their bodies against the metal door. A few moments later Andrew was brought in by some other soldiers. After some tea and having our wounds cleaned, we were escorted by the Army back to the hotel."

Van Agtmael lost all of his images, but, he says, "it's a small price to pay."

He plans on staying a few more days in Cairo, but, he admits, "my gut is telling me to take a break."

Visit the Magnum Photos website for more information on Peter van Agtmael.