Ending its three-week offensive against Hamas in the Gaza Strip that left over 1,200 people dead, Israel on Sunday declared a unilateral ceasefire, but Palestinian militants fired a barrage rockets into the Jewish state hours after the "fragile" truce took hold  stoking fears of fresh violence.

The ceasefire came into effect at 2 am local time (0530 hours IST) after Israeli Premier Ehud Olmert made an announcement in this regard last night.

"We have reached all the goals of the war, and beyond," Olmert said, adding, "Hamas was hit hard, in its military arms and in its government institutions. Its leaders are in hiding and many of its men have been killed."

The truce was announced after 22 days of fighting that killed over 1,200 Palestinians, half of them civilians, according to Palestinian and UN officials. Thirteen Israelis, including three civilians, also died.

Responding to the Israeli announcement, Hamas said it did not consider Olmert's declaration a ceasefire as long as Israeli troops remain in the Palestinian territory.

"The troops on the ground are a declaration of war against the Palestinians," Osama Hamdan, a representative of Hamas which rules Gaza, was quoted as saying.

Hours after the truce came into effect, Gaza militants fired a volley of rockets into southern Israel and exchanged fire with troops in northern Gaza, reports reaching Jerusalem said.
 
After the rocket attack, Olmert warned that the ceasefire was being reassessed. It has been proved again on Sunday morning that the ceasefire 'is fragile and it has to be reassessed on minute by minute basis', he was quoted as saying by the media.