GAZA CITY, Gaza Strip - Israel yesterday widened its deadliest-ever air offensive against Gaza's Hamas rulers, pounding smuggling tunnels and a central prison, sending more tanks and artillery toward the Gaza border and approving a reserves call-up for a possible ground invasion.

Israeli leaders said they would press ahead with the Gaza campaign, despite enraged protests across the Arab world and Syria's decision to break off indirect peace talks with the Jewish state. Israel's foreign minister said the goal was to halt Gaza rocket fire on Israel for good, but not to reoccupy the territory.

With the two-day death toll nearing 300 yesterday, crowds of Gazans breached the border wall with Egypt to escape the chaos. Egyptian forces, some firing in the air, tried to push them back into Gaza and an official said one border guard was killed.

Hamas, in turn, fired rockets deeper than ever into Israel, near the Israeli port city of Ashdod.

Yet Hamas leaders were forced into hiding, most of the dead were from the Hamas security forces, and Israel's military intelligence chief said Hamas' ability to fire rockets had been reduced by 50 percent. Indeed, Hamas rocket fire dropped off sharply, from more than 130 on Saturday to just over 20 rockets yesterday. Still, Hamas continues to command some 20,000 fighters.

Israel's intense bombings - some 300 air strikes since midday Saturday - wreaked unprecedented destruction in Gaza, reducing entire buildings to rubble.

Across the territory, grieving families pitched traditional mourning tents of green tarp outside the homes. Yet the rows of chairs inside these tents remained largely empty, as residents cowered indoors for fear of new Israeli strikes. Plumes of gray smoke rising into the sky marked the site of the latest Israeli attacks.

Even for war-weary Gazans, who've lived through countless Israeli incursions, air attacks and months of bitter Palestinian infighting, the latest surprise Israeli air offensive was unusually traumatic. In all, more than 290 people - most of them Hamas policemen, but also 20 children - were killed in some 300 Israeli air attacks over two days.

On Saturday, shortly after Israel unleashed the deadliest-ever offensive against Hamas and its rocket squads, hospital morgues quickly overflowed. In the initial chaos, the dead were wrapped in blankets and lined up on the ground, as frantic relatives searched for their loved ones.

Yesterday, 25 unclaimed bodies still lay in the morgue of Gaza's largest hospital, Shifa, their faces disfigured beyond identification. In the southern town of Rafah, residents held a mass funeral for 14 people, including two brothers, and a father and son, all of them members of the Hamas security forces.

After nightfall, Israeli aircraft attacked a building in the Jebaliya refugee camp next to Gaza City, killing a 14-month-old baby, a man and two women, Gaza Health Ministry official Dr. Moaiya Hassanain said. Israeli aircraft also bombed the Islamic University and government compound in Gaza City, centers of Hamas power. Witnesses saw fire and smoke at the university, counting six separate airstrikes there just after midnight.

Shlomo Brom, a former senior Israeli military official, said it was the deadliest force ever used in decades of Israeli-Palestinian fighting. "Since Hamas took over Gaza [in June 2007], it has become a war between two states, and in war between states, more force is used," he said.

European leaders called on both Israel and Hamas to end the bloodshed.

French President Nicolas Sarkozy spoke yesterday with Palestinian President Mahmoud Abbas, who leads a rival government to Hamas in the West Bank, and condemned "the provocations that led to this situation as well as the disproportionate use of force."

The White House was mum about the situation in Gaza yesterday after speaking out expansively on Saturday, blaming Hamas for provoking Israel's retaliatory strikes.

In the most dramatic attacks yesterday, warplanes struck dozens of smuggling tunnels under the Gaza-Egypt border, cutting off a lifeline that had supplied Hamas with weapons and Gaza with commercial goods. The influx of goods had helped Hamas defy an 18-month blockade of Gaza by Israel and Egypt, and was key to propping up its rule.

Yesterday's blasts shook the ground several miles away and sent black smoke high into the sky. Earlier, warplanes dropped three bombs on one of Hamas' main security compounds in Gaza City, including a prison. Moments after the blasts, frantic inmates, their faces dusty and bloodied, scrambled down the rubble. One man, still half buried, raised a hand to alert rescuers.

Gaza's nine hospitals were overwhelmed. Hassanain, who keeps a record for the Gaza Health Ministry, said more than 290 people were killed over two days and more than 800 wounded. *