At least seven people, including a child, have been killed in an Israeli operation in the southern Gaza Strip, Palestinian officials have said.
Witnesses said about 50 tanks, backed by bulldozers, pushed further into Gaza, taking up positions near Rafah.
The Israeli military said it carried out air strikes on militant targets, including a group which it said was trying to launch an anti-tank rocket.
Israel began its Gaza operations after the capture of a soldier on 25 June.
Cpl Gilad Shalit, 19, was captured in a cross border raid by Palestinian militants.
In the latest Israeli air and artillery strikes, most of those killed were Palestinian militants, Palestinian sources said.
A young boy was among those killed and 26 people were injured, several critically. Some reports suggested one other civilian was among the dead.
The UN says 35 children have been killed during Israeli operations in Gaza in the past month.
The Israeli military confirmed that an operation in south Gaza was under way. It said a missile was fired after militants targeted its troops with a rocket propelled grenade.
The Israeli army says its forces are there to make arrests and to search for tunnels used by Palestinian militants to move weapons in and out of Gaza.
Earlier, an Israeli man in the coastal city of Ashkelon was injured by a Qassam rocket fired by Palestinian militants in the Gaza Strip.
More than 140 Palestinians, many civilians, have been killed since Israel's Gaza operations began.
On Wednesday UN officials renewed warnings of a humanitarian crisis in the territory, which is suffering food, water and electricity shortages as well as repeated Israeli incursions, air strikes and shelling.
Israel says it needs to target civilian areas because that is where Palestinian militants, who regularly fire rockets into Israel, are based.