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Israeli aircraft struck armed Palestinians in northern Gaza early Friday after the bloodiest day of clashes in the strip since Israel withdrew last summer.

Twenty-four Palestinians and one Israeli soldier were killed in fighting that began on Thursday, pitting militants armed with assault rifles and rocket-propelled grenades against Israeli tanks and attack helicopters.

Israeli troops invaded two northern towns near its border on Thursday, expanding a ground offensive to win freedom for a soldier captured by militants and put Israel out of the militants' increasingly longer rocket range.

After sunrise Friday, Israel renewed its assault in northern Gaza with two airstrikes, killing one militant from the Palestinians' ruling Hamas Party, and wounding three, Hamas and hospital officials said. The military said aircraft fired at four armed Palestinians where there had been exchanges of fire. Two were wounded in the second airstrike, hospital officials said.

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Israel, meanwhile, signaled its intention to reduce the scope of its operation in one of the invaded towns. Lt. Col. Yaniv, a battalion commander, said he expected troops to wind up their mission in parts of Beit Lahiya within a day or two. Those areas include a neighborhood where Palestinian militants fired rockets into the southern Israeli city of Ashkelon earlier in the week, reaching significantly farther inside Israel than at any time before.

Amid the fighting, there was still no word on the fate of Cpl. Gilad Shalit, captured June 25 by Hamas-affiliated militants.

Israeli leaders have singled out Hamas as their chief enemy, and the Palestinian prime minister, a Hamas leader, accused Israel of trying to bring down his government.

Dozens of Palestinian casualties, including many wounded women and children, crowded the emergency rooms and corridors of Gaza hospitals, already suffering from shortages of medical supplies because of a closure Israel clamped on the territory after the soldier's capture.

After touring Gaza's main hospital Thursday evening, Palestinian Prime Minister Ismail Haniyeh of Hamas called for international intervention to stop the Israeli offensive, which he called a "crime against humanity."

Haniyeh called the Israeli push "a desperate effort to undermine the Palestinian government under the pretext of a search for the missing soldier."

His Hamas movement, with a history of violence against Israel, was voted into power in a January parliamentary election.

Interior Minister Said Siyyam of Hamas issued the Palestinian government's first call to arms since Israeli ground forces invaded Gaza, appealing on Thursday to all security forces to fulfill their "religious and moral duty to stand up to this aggression and cowardly Zionist invasion." The security forces are dominated by officers loyal to the rival Fatah Party, and there was no immediate response to his appeal.

Israel insisted it was not planning to reoccupy Gaza, but military commanders said they had orders to win the soldier's release and prevent militants from firing rockets, even if that meant repeated short-term incursions.

Palestinians fired 12 rockets at Israel in the 24 hours that led up to Friday's early morning airstrikes. Six landed in Israeli territory, the military said, and one caused damage in the town of Sderot, just outside Gaza. No one was hurt.

In response, Israel on Thursday sent troops and tanks into two densely populated northern Gaza towns where militants often fire rockets, Beit Lahiya and Beit Hanoun.

Dozens of Palestinian casualties, most of them militants but including many wounded women and children, crowded the emergency rooms and corridors of Gaza hospitals, already suffering from shortages of medical supplies because Israel closed the territory after the soldier's capture.

After touring Gaza's main hospital Thursday evening, Palestinian Prime Minister Ismail Haniyeh of Hamas called for international intervention to stop the Israeli offensive, which he called a "crime against humanity."

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Haniyeh called the Israeli assault "a desperate effort to undermine the Palestinian government under the pretext of a search for the missing soldier." His Hamas movement, with a history of violence against Israel, was voted into power in a January parliamentary election.

Throughout the day, Israeli aircraft targeted Palestinian militants with missile strikes, while Israeli tanks took up positions among tightly packed Palestinian homes. Apache helicopters hovered overhead, firing flares and machine guns to support ground forces engaged in fierce skirmishes with masked Palestinian gunmen.

Militants, many wearing in black masks, sneaked down narrow alleys to approach the Israeli forces and open fire with AK-47s and rocket-propelled grenades.

Lt. Col. Yaniv, a battalion commander, said resistance was stiff. "The Palestinians have been firing rocket-propelled grenades, automatic weapons and setting off explosive devices," said Yaniv, who gave only his first name under military regulations.

It was not clear how many civilians were killed, but Hamas said seven of its militants died in the clashes.

During lulls in the fighting, some Palestinian women and young children fled their homes to evacuate the area on foot.

Ali Ajrami, a tailor living in a farm house in Beit Lahiya, was trapped with his nine children in one room after Israeli tanks parked behind his house and special forces took positions on the rooftops of neighboring buildings.

Gunfire could be heard nearby.

"We are trapped. I don't know what to do," he said. Ajrami said he had stocked up food and diesel fuel before the offensive, but was struggling to keep his children indoors.

An Israeli soldier died in one of the skirmishes — the first Israeli casualty. Israel Radio and Army Radio said the army was checking the possibility that he was killed by errant Israeli gunfire. The army spokesman's office said he was killed by a Palestinian gunman.