At least nine Palestinians have been killed in fresh Israeli operations in Gaza and the West Bank.
The Israeli military began its offensive in Gaza three weeks ago
Under heavy gunfire Israeli tanks entered Mughazi refugee camp in the central Gaza Strip before dawn.
At least six Palestinians, including a number of militants, were killed in the latest incursion in a three-week operation in Gaza by the Israelis.
Later, three Palestinians were shot by Israeli troops in the West Bank city of Nablus, Palestinian sources said.
Civilians are among the dozens of Palestinians who have died in the Israeli assault on Gaza, launched after an Israeli soldier was captured by Palestinian militants.
The Israeli army said five of its soldiers were injured in the operation, which saw some 30 Israeli armoured vehicles in the camp by sunrise, residents told the Associated Press news agency.
Israel is also reported to have carried out air strikes on the camp.
An army spokeswoman said the operation aimed "to target terror infrastructure" in the camp, "as part of the ongoing effort in which one of its main targets is getting back [captured Israeli Cpl] Gilad Shalit and stop the launching of Qassam rockets," news agency AFP reported.
At least 45 Palestinians, including children, were wounded, Palestinian hospital officials said.
According to Israel Radio, Israel is also shelling sites in Gaza which were used to launch Qassam rockets over into the western Negev on Tuesday evening.
Israel launched its military offensive in the Gaza Strip three weeks ago after Cpl Shalit was abducted by militants linked to Hamas's military wing.
Its Gaza assault prompted international calls for restraint, but a UN resolution urging Israel to stop the offensive was vetoed by the United States at the Security Council last week.
In its raid on Nablus, soldiers surrounded a security building in a bid to capture militants apparently hiding inside.
Three Palestinians died in exchanges of fire with the troops, who reportedly used megaphones to demand those inside the building come out.
Dozens of Palestinians were then arrested, reports said.