At least 31 Palestinians have been killed today and more than thousand taken into custody.

The operations continued into Tuesday afternoon, reports came in from northern Israel that at least seven Israelis had been killed in an attack on a bus.

The Israeli army said the bus had been hit by gunfire and grenades close to the town of Shlomi near the Lebanese border, killing at least seven Israelis. Three gunmen had been killed by soldiers and police. The attack raised the specter of a new front opening in the conflict. The identity of the attackers could not be immediately confirmed and it is not yet known if they came from Libanon side.

The Israeli offensive began overnight in the Gaza Strip when tanks backed by Apache helicopters rolled into the Jabalya refugee camp in Gaza.

In the resulting gun battle, at least 18 Palestinians died - four of them members of the militant group Hamas - and many were wounded. Civilians fled the area in terror.

As the first funeral processions wound their way through Gaza City, Apache helicopters were in the air over Khan Younis and Rafah, while ground troops continued an incursion into the centre of the Gaza Strip. Later on Tuesday morning, the Israeli army seized control of most of the West Bank city of Ramallah.

Eyewitnesses said that more than 130 Israeli tanks were involved in the operation, which has seen the deaths of several Palestinians.