Jerusalem ? Israel’s deputy defense minister warned of disaster in the Gaza Strip after Palestinian rocket fire grew more ominous Friday with an assault on an Israeli city. Gaza’s unbowed Hamas rulers promised to fight on.

Meanwhile, Hamas said a 13-month-old girl and three other civilians were killed in an Israeli strike on Beit Hanoun, a northern town in Gaza where Palestinian militants often launch rockets at Israel. But local residents said a militant rocket fell short and landed in the area of the baby’s house.

Deputy Defense Minister Matan Vilnai told Army Radio that because of the attacks, Israel had “no other choice” but to launch a massive military operation in the Gaza Strip.

“As the rocket fire grows, and the range increases … they are bringing upon themselves a greater ‘shoah’ because we will use all our strength in every way we deem appropriate, whether in airstrikes or on the ground,” Vilnai said.

The Hebrew word “shoah” most often refers to the Holocaust but Israelis use it to describe all sorts of disasters. A spokesman for Vilnai, Eitan Ginzburg, said the deputy defense minister never intended it as a reference to the Holocaust but used the word “shoah” to denote a disaster.

The violence comes ahead of Secretary of State Condoleezza Rice’s visit to the region next week. It also clouds already troubled efforts by Palestinians and Israel – and backed by Washington – to reach a peace accord by year’s end.

The Israeli military has completed preparations for a major ground offensive and notified the government it is ready to move, defense officials said. An invasion is not expected for the next week or two, in part because the military prefers to wait for clearer weather, the officials said.

Sami Abu Zuhri, a Hamas spokesman, dismissed Vilnai’s comments, saying: “We are not afraid of these threats.”

The violence highlights Hamas’ role as a possible spoiler in peace talks. Palestinian President Mahmoud Abbas could find it difficult to negotiate with Israel if there is an invasion of Gaza, and Israel’s fragile governing coalition will find it hard to make concessions while Palestinian rockets reach deeper into its territory.