JERUSALEM (AP) - Israeli Prime Minister Ehud Olmert gave his military a "free hand" to hit Gaza militants after a rocket slammed into a house in an Israeli town following a visit there by the new U.N. humanitarian chief, who called for an end to the daily salvos.

Speaking in Jerusalem at a gathering Sunday evening of the Conference of Presidents of Major American Jewish Organizations, Olmert said he would not allow a humanitarian crisis to develop in Gaza, but the people of Gaza could not live normal lives while Israelis across the border were constantly targeted by rockets.

Olmert said Israel’s military has a "free hand" to hit Gaza militants. "We will reach out for anyone involved in perpetrating terrorism against Israelis, and we will not hesitate to attack them in order to stop them," he said. "That applies to everyone, first and foremost Hamas. Hamas is in charge of Gaza."

Early Sunday Israeli ground forces entered Gaza, backed by aircraft. In clashes, three Palestinian militants and a civilian were killed, and an Israeli soldier was seriously wounded.

The military said the target was the Gaza "terror infrastructure," and more than 80 Palestinians were taken for questioning.