In response to the recent string of fatal Hamas rocket attacks, Israel is likely to conduct a medium-size military operation against the Islamist group before agreeing to a cease-fire in the Gaza Strip, senior defense officials told The Jerusalem Post on Saturday.

A final decision on Israel's course will be made on Tuesday during a meeting between Prime Minister Ehud Olmert, Defense Minister Ehud Barak and Foreign Minister Tzipi Livni. Barak, officials said, favored first striking at Hamas and only then agreeing to a truce.

"Under the current circumstances, accepting a cease-fire would appear as if we are giving in to Hamas's demands and ultimatums," a senior defense official said, adding that an operation would likely be launched soon.

According to the new strategy, the IDF will not reoccupy the Gaza Strip but will instead initiate an incursion to make Hamas "pay a price," and afterward agree to a cease-fire.

On Thursday, 51-year-old Amnon Rozenberg was killed by a mortar shell outside the paint factory where he worked at Kibbutz Nir Oz.

Senior defense officials said over the weekend that both Olmert and Barak favored ultimately accepting a cease-fire in Gaza according to Israel's two-stage proposal.

The first stage is a cessation of Hamas terrorism and IDF operations, and the second stage is lifting the blockade of Gaza in exchange for the release of kidnapped Cpl. Gilad Schalit.

Government sources said the mortar attacks that killed three people in the last month on kibbutzim near the Gaza Strip had pushed Barak into a position where he now supported large-scale military action.

According to these sources, the kibbutzim in general - there are around 20 of them near Strip - are Barak's political base inside the Labor Party, and are increasingly pressuring him to take significant action.

Both Olmert and Livni, the sources said, had for some time been in favor of military action, afraid that if the cease-fire proposal was accepted, Hamas would continue smuggling arms into Gaza, something that would make any future IDF incursion more difficult.

Government officials said it was not clear whether the security cabinet would be convened to give final approval to a military operation into Gaza, since two months ago that forum authorized Olmert, Barak and Livni for an incursion. Furthermore, the officials said, there was clear support in the security cabinet for military action.

The sources said that after continuously saying that the decision would be made soon, it was unlikely that it could be put off any longer, especially as the rocket and mortar attacks continued and Israeli civilians were being killed.

Olmert, upon his arrival from Washington on Friday, reiterated at Ben-Gurion Airport that the current situation was untenable.

"According to the information as it is now, the pendulum is much closer to tough military action," the prime minister said.

Also on Saturday, Barak ordered the IDF to impose a closure on the West Bank and the Gaza Strip until Shavuot ends on Monday evening.

On Friday, a number of Gazan rockets struck Israel, sending several people into shock and damaging property.

Early on Friday morning, an IDF soldier was moderately wounded by a sniper in the northern Gaza Strip.

The shooting took place after IAF aircraft bombed a Hamas outpost in northern Gaza overnight Thursday. According to Palestinian reports, one Hamas gunman was killed and 15 others were wounded.

The IDF said that the outpost was used by members of the cell that fired the mortar shell that killed Rozenberg on Thursday.