Associated Press
In Rafah in the Gaza Strip, a Palestinian youth stands in a balcony of a building damaged in years of conflict with Israel.

SDEROT, Israel — The residents of this Israeli border town, plagued by rocket fire from Gaza for the past seven years, woke up on Thursday to the start of a truce. They ventured out gingerly, unsure how long it would last.

"It's an illusion," said Meir Kroytoro, 46, a factory worker. "Calm for how long?"

The Israeli government has proved itself "a coward," he said. "It would have been better for the army to go into Gaza and finish the story once and for all."

At 6 a.m., the cease-fire between Israel and Hamas, the Islamic group that controls Gaza, went into effect. Just then the sun was rising over Sderot. It did not immediately burn off the early morning mist over Gaza — mist used in the past as cover for Palestinian militants to carry out attacks along the border only a mile or so away.

The truce, a promise of calm reached through painstaking talks mediated by Egypt, holds, in theory, the possibility of a new era in Israel's relations with Gaza and Hamas. But few Israelis envision that. Instead, they say they believe that Hamas will exploit the quiet to increase its strength or will fail to control other militant groups in Gaza, making a military confrontation unavoidable in the end.

So rather than prompting congratulations, the truce was ushered in with tough declarations on both sides.

"This calm is fragile and is liable to be short-lived," Ehud Olmert, the prime minister of Israel, proclaimed on Wednesday night. "Hamas and the other terrorist organizations have not changed and have not become patrons of peace. These are contemptible and bloodthirsty terrorists."

On Thursday morning, Hamas announced that any Israeli infraction would meet with an immediate response.

There was widespread expectation in Gaza that border crossings would soon open, allowing freer movement of people and goods. As part of the truce agreement, Israel is supposed to start easing the sanctions imposed after Hamas seized control of Gaza last June.

In this and several other aspects, the truce agreement appeared to run contrary to Israel's stated policy of trying to squeeze Hamas out of power in Gaza while bolstering the more moderate and secularist Palestinian Authority, which is now confined to governing in the West Bank. Many critics of the Israeli government, as well as Palestinians, thus chalked the agreement up as a victory for Hamas.