The site of an early morning air strike in the Gaza Strip.

Witnesses say at least four people were wounded in the attack by Israeli aircraft, hours after five rockets fired from the enclave hit southern Israel.

Israel said the strike, as well as an exchange of fire between Palestinians and the Israeli army, came after a barrage of rockets landed in the Jewish state - though no damage or injuries were reported.

The retaliatory air strike comes a week after another strike on Gaza killed two Palestinian gunmen and the leader of an al Qaeda-linked militant group.

Israel holds Hamas responsible for any attacks launched from Gaza, even though the group has recently mostly refrained from violence.

But Hamas does reject permanent peace with Israel and has controlled Gaza since 2007.