After two months of training in Egypt, some 500 Palestinian security forces affiliated with the Fatah faction returned to Gaza through the Rafah border crossing point, security officials said Wednesday. The troops came to Egypt in mid-March for training at an Egyptian police camp in the northern Mediterranean city of Alexandria, an Egyptian security official said, speaking on condition of anonymity because of the sensitivity of the issue. The forces were trained in the use of automatic rifles, curbing riots and on tactics of street battle control, according to the official. Hani Jabbour, a Palestinian official at the Rafah border checkpoint, said the Fatah troops drove through the checkpoint back into Gaza on Tuesday in police buses and unarmed. The Palestinians took control of Rafah in a US-brokered agreement on Gaza crossings, reached after Israel's pullout from the coastal strip in September 2005. Under the deal, the European observers were deployed to watch the Palestinian inspectors and make sure no militants or weapons are smuggled through. Maria Telleria, spokeswoman for the European monitors, said the Fatah troops numbered 450 Palestinian members of the presidential guard. The discrepancy in the numbers could not immediately be reconciled. Telleria said the Rafah crossing was opened only for about one hour and a half around noon Tuesday for the troops to pass, with the permission of the Israelis. The Palestinians were not in uniform but their identity cards identified them as members of the presidential guard. The Rafah crossing usually opens only briefly twice a week. Gaza is witnessing the worst fighting between Palestinians' main factions Fatah and Hamas, with some 41 people killed in the infighting this week and dozens more injured. The Fatah side has sustained most of the casualties. The violence threatens to bring down the Palestinians' fragile Hamas-Fatah unity government, and bring the Palestinians to the brink of an all-out civil war. At the core of the fighting is the unresolved power struggle between Hamas, which won parliament elections last year, and the more moderate Fatah faction of Palestinian Authority Chairman President Mahmoud Abbas, which dominated Palestinian politics for four decades. Following a year in power and crippled by an international aid boycott, Hamas agreed earlier this year to bring Fatah into the government. However, differences between the two sides remain, particularly over who would control the Palestinian security forces.