Only hours after two Israeli army officers were killed in an ambush in central Gaza, Israeli forces raided southern Gaza strip on Monday, Palestinian sources have said. These are the first Israeli deaths in fighting in the occupied territories in a month. Two Palestinian militant factions claimed responsibility for killing the army officers. A gunman was later shot dead. Witnesses said about 40 tanks and armoured vehicles entered Rafah refugee camp on the Gaza-Egypt border. Israeli soldiers shot dead a 50-year-old man in the camp and critically wounded two gunmen, one of whom died later, Palestinian medics said. An unnamed Israeli military source told Reuters soldiers opened fire at Palestinians trying to plant or detonate an explosive device. Witnesses said gunmen fired at troops as they entered the camp. Israel has sporadically targeted Rafah to try to disrupt attempts by Palestinians to smuggle weapons across the border through a network of tunnels. Israel has demanded a Palestinian crackdown on resistant groups and has warned that if the road map fails, it will take unilateral action to separate itself from the Palestinians, taking some land they want for a state. Palestinians say Israel must meet its own obligations by removing Jewish outposts and freezing settlement construction on occupied land, as well as halt work on a wire and concrete barrier being built through the West Bank. Israel says the barrier is necessary for its security to keep out resistant bombers and gunmen.