A heavy rocket barrage from the Gaza Strip struck southern Israel today, police said, a day after Israeli forces killed three Palestinian militants in the enclave.

Police said there were no immediate reports of casualties after "a number of waves of rockets" hit. In the Gaza Strip, the Islamic Jihad group claimed responsibility for the attack.

"It's a barrage such as we haven't seen for two years," Haim Yellin, a local municipal official in the south, said on Army Radio, which reported that some 30 rockets had been fired.

Sirens sounded in parts of southern Israel to warn residents to take shelter.

A day earlier, an Israeli air strike killed three Islamic Jihad members who the group said had fired motar bombs at Israeli troops that entered the Gaza Strip through Israel's border fence.

Israel pulled its troops and settlers out of the territory, now run by Hamas Islamists, in 2005. But it maintains a naval and air blockade and severely restricts the overland movement of people and goods across the volatile border,