GAZA CITY, Jan 3: Israeli troops clashed with Hamas fighters as they advanced into Gaza Strip on Saturday in the first ground combat of an eight-day offensive on the Palestinian enclave, witnesses and the Israeli army said.

Columns of tanks backed by helicopters crossed the boundary fence from four directions into the northern Gaza Strip under the cover of darkness, a Palestinian witness said.

An Israeli military spokeswoman said the aim was to seize areas from where Hamas was launching rocket attacks on southern Israel. “The objective is to destroy the ‘Hamas terror infrastructure’ in the area of operations,” Major Avital Leibovitch said.

A Hamas spokesman said in a televised speech that Gaza would “become a graveyard” for Israeli soldiers. The spokesman, Ismail Radwan, appeared on Al Aqsa TV shortly after Israel launched the ground offensive. In another message, Hamas warned Israeli forces that “Gaza will not be paved with flowers for you. It will be paved with fire and hell”.

Hamas has long prepared for Israel’s invasion, digging tunnels and rigging some areas with explosives. At the start of the offensive, Israeli artillery hit some of the border areas, apparently to detonate hidden explosives.

A witness said fighting had broken out in northern Gaza as Hamas fighters took on the Israeli forces. Israeli television showed soldiers in battle gear advancing on foot.

Large numbers of forces were involved in the operation, including infantry, tanks, engineers, artillery and intelligence, the Israeli military said in a statement.

The ground offensive could take many days, the chief military spokesman said. “This won’t be a school outing,” Brigadier Avi Benayahu told Israeli television. “We are talking about many long days.”

A senior Hamas official said the militants had killed a number of Israeli soldiers but there was no word from Israel on any casualties.

Hours before the advance, an Israeli air strike killed 11 Palestinian worshippers, including children, and wounded dozens at a mosque in Beit Lahiya, Hamas officials and medics said.

The mosque raid brought the Palestinian death toll to at least 446, with about 2,050 wounded, in the worst sustained bloodshed in decades of the conflict between Israel and the Palestinians.—Agencies