The Egyptians threatened on Wednesday to close the Rafah border crossing until further notice after hundreds of Palestinians stormed the terminal and threw stones at Egyptian soldiers. At least six Egyptian border guards were lightly wounded in the incident. Egyptian troops used water cannons to disperse the protesters. The incident began when the Egyptian authorities opened the Rafah border crossing for a few hours to allow Palestinian patients to leave the Gaza Strip for medical treatment. The move was also aimed at allowing some 100 Palestinians stranded on the Egyptian side to return to the Gaza Strip. Shortly after the border crossing was reopened, hundreds of angry Palestinians stormed the terminal and started hurling stones at the Egyptian guards, eyewitnesses said. They added that Hamas's security forces also intervened and prevented the Palestinians from infiltrating the border. Following the incident, the Egyptians warned the Hamas government against allowing Palestinians to breach the border. Sources close to Hamas said the warning was delivered to the Hamas government by top Egyptian security officials. A Hamas official in the Gaza Strip accused the Egyptians of failing to fulfill their promise to reopen the Rafah border crossing in the wake of the cease-fire agreement with Israel. "The Egyptians are participating in the siege on the Gaza Strip," the official said. "They are aggravating the suffering of the Palestinians by refusing to reopen the border crossing." According to the Hamas official, the Egyptians are refusing to allow some 1,500 Palestinians to leave the Gaza Strip for medical treatment. He said another 6,000 Palestinians remained stranded on the Egyptian side because the Egyptians were refusing to allow them to return to the Gaza Strip. Egyptian sources, meanwhile, said the riots were spontaneous, unplanned and triggered by people at the crossing. According to the sources, Egypt's policy is to allow a limited number of people through the crossing for humanitarian purposes, much the same way Israel let a few humanitarian cases through the Gaza crossings before the cease-fire. The sources said that some 100 people went through the crossing on Tuesday, and 20 before the rioting started on Wednesday. Many of those coming through the crossing, the sources said, were Egyptians who were trapped on the other side of the border. One Israeli government official said Egypt was in no great hurry to open the crossing because of concern that it would lead to a flow of Hamas activists into Egypt, something Cairo would like to prevent. Egyptian sources said the Rafah crossing would only be opened permanently after kidnapped IDF soldier St.-Sgt. Gilad Schalit was released.