ISRAELI troops have begun an advance into Gaza this evening after an eight day offensive involving 800 air strikes.

The troops were supported by helicopters, the Israeli army said.

Witnesses reported that the first ground offensive of the latest action against Hamas involved a small number of military vehicles which crossed into the Palestinian enclave.

An Israeli military spokeswoman confirmed the ground advance and said its purpose was "to destroy the Hamas terror infrastructure in the area of operations".

Major Avital Leibovitch added: "We are going to take some of the launch areas used by Hamas."

Israeli tanks and troops had been massed on the border for days.

More than 400 people in Gaza have been killed and some 1,700 wounded since Israel began its offensive.

Four Israelis have also died in cross-border rocket attacks by Hamas and other militant groups.