At Least 13 Palestinians Killed As Israeli Military Enters Gaza

"Islamic Jihad activity, and unfortunately by Hamas, too, from time to time, is entirely directed to attack Israeli civilians," said Hanegbi, a lawmaker from Olmert's Kadima party, referring to the two largest armed Islamic movements at war with Israel. "They did not stop for even one day. Israel, therefore, cannot stand idly by and leave the arena to the enemy's unilateral actions."

Israeli military officials said Israeli tanks and troops were operating in Gaza City and several villages east of Khan Younis, the largest city in the central strip, to stop Palestinian rocket fire, discover weapons depots and smuggling tunnels, and root out gunmen. Israeli officials said two soldiers were lightly wounded in the operation.

One rocket and several mortars were fired at Israel on Wednesday during the fighting, but fell near the Gaza-Israel boundary without causing injury or damage. Last month, two Israelis were killed in rocket attacks, which have recently declined in frequency.

The vast majority of the casualties came during street fighting between Israeli infantry and gunmen from a variety of Palestinian militias. The exception came around noon when a car exploded in Gaza City and killed Raed Fanuna, a senior commander of Islamic Jihad, a small group that has shunned the Palestinian political process.

The Israeli military denied involvement in the blast, and Islamic Jihad gunmen in Gaza said the car had been rigged to explode. They blamed Israeli "collaborators" for the death, and vowed to continue firing rockets into southern Israel.

By midafternoon, Israeli forces had withdrawn from the Shajaiyeh neighborhood but remained in central Gaza.

Special correspondent Islam Abdulkareem in Gaza contributed to this report.