Southern Israel was pounded by a number of rockets fired from the Gaza Strip on Sunday morning, hours after an Israeli unilateral ceasefire went into effect.

At least five rockets landed in the southern Israeli town of Sderot and the nearby area, causing no casualties or damage, local news service Ynet reported.

The Jewish state has vowed to end the rocket fire by the so-called Operation Cast Lead.

Also in the morning, the Israeli army confirmed that it opened fire after Gazan militants fired at Israeli troops in the Gaza Strip.

Meanwhile, Palestinian militants claimed on Sunday their responsibility for fresh attacks on Israel after the Jewish state's unilateral ceasefire.

The attacks include at least five rockets fired into Israel, and gunbattles in eastern Gaza City and northern Gaza Strip this morning.

The barrage and exchange of fire came after an Israeli unilateral ceasefire, declared by Prime Minister Ehud Olmert late on Saturday night, went into effect at 2:00 AM (0000 GMT) on Sunday, during which Israeli troops are supposed to fire only in response to attacks from the Palestinian side.

Olmert said the Israeli army would remain in Gaza for an unspecified period of time, while Hamas has demanded the " occupying forces" withdraw as soon as possible and vowed to resist until the pullout of Israeli troops and lifting of the Israel- imposed blockade.