The US State Department on Tuesday asked its citizens to leave the Gaza Strip immediately and to defer travel to Israel or the West Bank in light of the volatile situation there.

"The Department of State warns US citizens to depart Gaza immediately and to defer travel to Israel, the West Bank and Gaza due to current safety and security concern," the State Department said in a statement.

"The situation in Israel, Jerusalem, Gaza and the West Bank remains extremely volatile with continuing terrorist attacks, confrontations and clashes," the statement said.

Americans who remain in Israel, the West Bank and Gaza should avoid going to such public places and crowded venues such as restaurants and cafes, shopping centers, market areas, pedestrian zones, public buses and bus stops, the statement said.

At least three Palestinians were killed and 15 others injured on Tuesday morning when Israeli Apache helicopters fired three missiles at the Rafah refugee camp in the southern Gaza Strip.

Meanwhile, the Islamic Resistance Movement (Hamas) has threatened to continue its rocket attacks to the southern Israeli town of Sderot unless the Israeli army stops its military actions in Gaza.