JERUSALEM AND GAZA CITY — Israeli warplanes and helicopters bombarded military targets across the Hamas-ruled Gaza Strip on Saturday and today, retaliating for Palestinian rocket fire into Israel with one of the deadliest assaults in the history of the 60-year conflict.
As Palestinian medical officials put the death toll at 271 and said many were unarmed civilians, the scale of the bloodshed unsettled the Middle East and alarmed world leaders involved in Israeli-Palestinian peace efforts.
Hamas officials called for a new Palestinian uprising against the Jewish state and a renewed wave of suicide bombings. Despite the heavy blow to their paramilitary organization, Hamas fighters in Gaza launched at least 110 rockets into Israel, killing a man and wounding six people in the border community of Netivot.
Israeli officials warned that the surprise offensive, apparently aimed at restoring a recently lapsed cease-fire on terms more favorable to Israel, was only beginning. Hundreds of Israeli troops massed along the Gaza border early today, and civilians on both sides braced for heavy combat in the days ahead.
Prolonged fighting in Gaza would make it difficult for the Palestinian Authority's more moderate leadership in the West Bank to continue peace talks with Israel, a process guided over the last year by President Bush and a high priority for his successor, Barack Obama.
The Bush administration put the onus on the militant Islamic group. "Hamas' rocket attacks into Israel must cease if the violence is to stop," White House spokesman Gordon Johndroe said. But he added, "The United States urges Israel to avoid civilian casualties as it targets Hamas."
The number of civilian casualties in Gaza was unclear. A Palestinian Health Ministry official, Moaiya Hassanain, estimated that one-third of those killed were non-combatants. He said 388 Palestinians were wounded in more than 100 airstrikes that came in waves from midday into the early hours of today.
"Palestine has never witnessed an uglier massacre," Ismail Haniyeh, leader of the Hamas government in Gaza, declared in a statement delivered from an undisclosed location.
In a statement, the Israeli military said it had targeted Hamas security headquarters, training camps and weapons depots. "The vast majority of the casualties are terror operatives," the statement said.
