Egyptian police officers blocked the Rafah crossing into the Gaza Strip on Friday to protest the kidnapping of seven of their colleagues by Islamist gunmen, witnesses said. Officers strung barbed wire across the border post and chained up the gates, leaving hundreds of Palestinians stranded on both sides of the fence, residents said. Gunmen abducted the seven security officers — policemen and a military border guard — on a road between the Sinai towns of El Arish and Rafah on Thursday and demanded the release of imprisoned militants in exchange for the seven men. A police officer was released shortly after the abduction as a sign of good will, but there was no information on the other six men, security officials said.