Israel ordered the Gaza-Egypt border crossing closed Thursday afternoon, just hours after it was partially opened for the first time in weeks, EU and Palestinian officials said. The crossing was to have been partially opened for two days to allow hundreds of people stuck in Gaza to leave after a weeks-long closure imposed during Israel's military offensive in the coastal strip. Israel informed European monitors that the crossing had to shut because there was a high security alert, officials said. "We received a warning from the IDF that for security reasons the terminal will be closed. They were saying there were suicide bombers or something like that," said Maria Telleria, a spokeswoman for the European border-monitoring mission there. Military officials said that Israel decided to close the border crossing due to specific threats. The crossing had been opened for people traveling from Gaza into Egypt only to allow students, business people and some people requiring medical treatment to travel to Egypt, Telleria said. About 500 sick people, many of them cancer patients, were given permission to cross the border for treatment, said Dr. Omar Shehada, a Palestinian Authority official responsible for overseas medical treatment. The border was closed after Hamas-allied operatives captured an Israeli soldier, Gilad Shalit, in a June 25 raid on an IDF army post. Israel feared the kidnappers would try to smuggle Shalit out of Gaza. Since the end of June, the border opened once before, allowing Palestinians stranded in Egypt to return to Gaza. "Since the border closed on June 25, we've been trying to open it, " said Telleria. "This is the longest period the border has been closed since the Europeans began (monitoring)," she said. The Palestinians, backed by EU monitors, took control of the Gaza-Egypt border after Israel pulled out of the coastal strip last summer. By midday, hundreds of Palestinians waited on the Egyptian side near the crossing, apparently hoping that their presence would pressure authorities to allow them to cross. "I came to this crossing more than 10 times - whenever I heard rumors that it would open," said Abdullah Abdel Rahman Belbasi, a 30-year-old Palestinian worker who entered Egypt a month ago for surgery to his arm after being shot. Also Thursday, doctors said that a 5-year-old Palestinian girl initially believed to have been killed by an Israeli military strike Wednesday apparently died after sustaining head injuries during a fall from a swing. The girl suffered a fractured skull and there were no signs of shrapnel, said Kazim Abu Libda, a doctor at Gaza's Shifa Hospital.