Jerusalem ? The Gaza Strip’s ruling Hamas militant group said Tuesday it has reached a cease-fire with Israel meant to halt a cycle of deadly Palestinian rocket attacks that rained hundreds of rockets on Israel in the past year and Israeli reprisals that have killed hundreds of Palestinians.

The accord, set to go into effect at 6 a.m. Thursday (10 p.m. CDT today), has the bigger aim of ending Israel’s yearlong economic blockade of Gaza and bringing home a captive Israeli soldier.

But the phased approach is prone to pitfalls, and past truces have quickly broken down. Israel cautiously promised a “new reality” if the rocket fire ends.

The announcement capped months of Egyptian-brokered negotiations that have been repeatedly marred by violence. The deal was first announced in Cairo by Egypt’s state-run news agency and quickly confirmed by Hamas. However, Hamas said it would respond to any Israeli attacks.

Underscoring the fragile situation, Israeli aircraft attacked three targets in southern Gaza, killing six Palestinian militants, Gaza medical officials said. In response, Palestinian militants fired seven rockets into Israel, the Israeli military said.

Still, after months of fighting, both sides seemed interested in a period of calm.

Israel wants to halt the incessant rocket and mortar attacks on its southern communities that have killed seven Israelis over the past year. Israeli reprisals have killed more than 400 Palestinians, many of them civilians, according to an Associated Press tally based on figures from hospital officials.

Israel also wants an end to Hamas arms smuggling into Gaza from Egypt, and the return of Cpl. Gilad Schalit, the Israeli soldier captured by Hamas-linked militants in a cross-border raid two years ago.

Hamas wants Israel to lift its crippling blockade of Gaza, which has led to widespread shortages of fuel, electricity and basic goods. Israel imposed the sanctions after Hamas violently seized control of Gaza last year, and has tightened the blockade recently in response to increased rocket fire.

Gaza Hamas leader Mahmoud Zahar said all the armed factions in Gaza are on board with the truce. Speaking after another Hamas official outlined details of the truce at a news conference, Zahar said Hamas will not put down its weapons, because he did not believe Israel would implement the cease-fire. “We don’t trust them, but let’s see,” he said.

Israeli Defense Minister Ehud Barak said Tuesday that no deal was in place yet. “It is too soon to announce a truce, and even when it begins, if it does, it is hard to evaluate how long it would last,” he said, adding, “The Israeli military is ready for any development.”

Past informal cease-fires with Hamas, most recently in November 2006, lasted only for several weeks. They were never formally signed because Hamas and Israel do not recognize each other. Israel and the Palestinians declared a truce in February 2005. Hamas, which killed scores of Israelis in suicide bombings, largely abided by the cease-fire until June 2006.