The Israeli military said on Sunday that it launched an airstrike to hit back Gaza militants' rockets attack earlier in the day after the Jewish state announced a unilateral truce late on Saturday night.

A spokesman from the military said that Israeli aircraft hit the launchers in the Gaza Strip that had fired rockets into Israel.

The retaliation came after southern Israel was pounded by a number of rockets fired from the Gaza Strip in the 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.

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

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

This is the first time that the rockets hit Israel only some seven hours after Israel's unilateral ceasefire took into effect.

Israeli Prime Minister Ehud Olmert Saturday evening announced a unilateral ceasefire in the Hamas-ruled Gaza Strip, beginning from 2:00 AM (0000 GMT) on Sunday.

The announcement came shortly after Israeli security cabinet voted in favor of a unilateral ceasefire in Gaza, where Israel Defense Forces (IDF) Cast Lead Operation had been going on in the past three weeks.