JERUSALEM -
Israeli troops and tanks thrust into the Gaza Strip's densely populated capital from three directions yesterday, drawing Hamas fighters into fierce combat in an offensive expanded by a fresh deployment of army reservists.
High-rise apartments shook, and smaller, targeted buildings crumbled in Gaza City under the force of Israeli artillery shelling and missiles fired from helicopters. Plumes of black smoke rose as Hamas fighters answered with mortars, automatic rifles and grenades.
The military said it killed 40 Palestinian fighters yesterday.
Palestinian medical officials put the death toll at 20 civilians and reported finding seven other bodies, presumably those of militants.
Israel reported no casualties of its own.
Yesterday's fighting was the heaviest since Israel attacked the Palestinian enclave Dec. 27 with the declared aim of halting years of rocket attacks on southern Israeli communities.
Troops moved into streets and buildings on Gaza City's northern, eastern and southern edges before dawn but pulled back after several hours, leaving it unclear whether Israel's leaders had ordered an all-out assault on the seat of Hamas' government and paramilitary force. The Mediterranean Sea borders the city on the west.
A decision to escalate the offensive would likely bring tens of thousands of Israeli reservists, who were called up late last month, into close urban combat with steep casualties on both sides.
Brig. Gen. Avi Benayahu said yesterday that the army had begun sending some reservists into Gaza, but he declined to say whether a new phase of the offensive was under way.
Prime Minister Ehud Olmert told his Cabinet in Jerusalem that Israel "is getting close to achieving the goals it set" in Gaza but added that "patience, determination and effort are still needed" to subdue Hamas.
Israel's ground forces entered Gaza on Jan. 3, the eighth day of punishing airstrikes, and quickly surrounded urban areas.
Yesterday's advance on Gaza City, the first significant movement of Israeli ground forces in a week, followed an unusual public appeal by the operation's commander, Maj. Gen. Yoav Galant, for a political decision to strike harder.
Intelligence officials told the Cabinet meeting that Hamas had suffered severe losses but was not finished fighting. Twenty rockets and mortar shells fell inside Israel on Sunday; one missile damaged an empty kindergarten in Ashdod.
