Israeli forces pounded Hamas symbols of control and Gaza's only power plant in one of the heaviest bombardments in the three-week conflict, trying to raise pressure on the Islamist group to accept Israel's terms for a cease-fire.

A strike early Tuesday engulfed the power plant in flames, forcing it to shut down and leaving many of the Palestinian territory's 1.8 million people without electricity. To Gazans, the attack on such a vital lifeline seemed aimed at weakening Palestinian support for the extended conflict both sides say they are ready to fight.

"With the power station gone, all of Gaza is going to collapse," said Mkhaimer Abusada, a political scientist at Gaza's Al Azhar University. "They're trying to put direct pressure on the Palestinians."

The strike on the plant added to the international alarm over soaring casualty figures, mostly in Gaza. The Palestinian death toll for the fighting that began on July 8 surpassed 1,200, according to Gaza's health ministry. On the Israeli side, 53 soldiers and three civilians have died.

As international efforts to achieve a cease-fire gain pace, a senior Israeli official said the military escalation was meant to force Hamas to choose between losing control of Gaza and yielding to Israel's terms for a sweeping disarmament of the territory.