RAFAH, Gaza Strip — Israeli forces fired a missile and four tank shells to hold back a large crowd of Palestinian demonstrators Wednesday, and shrapnel from the blasts killed at least 10 Palestinian children and teenagers and wounded 50 people, hospital officials said.
An Israeli army spokeswoman said soldiers fired warning shots toward an abandoned structure — and not the crowd — to try to stop 3,000 demonstrators marching toward the Rafah refugee camp, scene of a deadly Israeli offensive.
But witnesses saw at least one large explosion go off among the protesters. White smoke rose into the air as Palestinians carried the wounded — including children with bloodied faces — from the scene.
It appeared likely that Israel would break off its offensive — dubbed "Operation Rainbow" — in the Rafah refugee camp because of Wednesday's strike. One government official said the idea was being considered. The offensive, in search of gunmen and weapons-smuggling tunnels, was to have lasted more than a week.
Even before Wednesday's strike, the offensive drew international condemnation. The Bush administration said it was "very concerned" about Wednesday's incident and asked Israel for an explanation.
"We continue to follow this closely. We urge all parties to exercise maximum restraint," White House press secretary Scott McClellan said.
British Prime Minister Tony Blair condemned the Gaza offensive as "unacceptable and wrong," while Spanish Prime Minister Jose Luis Rodriguez Zapatero criticized Israel's tactics and urged a new commitment to the U.S.-backed "road map" peace plan.
Prime Minister Ariel Sharon's adviser, Raanan Gissin, said, "We regret any loss of human life ... in the course of our efforts to defend ourselves. There is no doubt that this requires a thorough investigation."
Israeli defense sources said senior officers, including the chief of staff, were in an emergency meeting to investigate the incident, which began as several thousand demonstrators marched from the town of Rafah to the nearby camp of the same name.
Associated Press Television News footage showed the crowd marching along a wide street when an explosion went off in their midst, sending white smoke into the air.
The wounded were evacuated by ambulance, private cars and donkey carts to the Rafah hospital. The hospital stairs and floors were drenched in blood as doctors shouted for help and blood donations. Hospital staff treated the wounded on the floors after quickly running out of beds.
Dr. Moawiya Hassanain, a senior Palestinian Health Ministry official, said 23 of the wounded were in critical condition and another 13 in "hopeless" condition. All the dead and most of the wounded were younger than 18, he said.
Brig. Gen. Ruth Yaron, the Israeli army spokeswoman, said forces fired warning shots — first a missile from a helicopter that hit an empty area, then machine guns and four tank shells — toward an abandoned structure.
Yaron did not say where the structure was in relation to the crowd.
"There was (Israeli) machine-gun fire into the direction of a wall in an abandoned structure, and also four tank shells were fired at this structure, at no point in the direction of the demonstrators," she said.
"At this stage, it's possible, that's our assessment, that there were casualties as a result of the tank shells that were fired."
Palestinian officials accused Israel of committing a war crime.
Physicians for Human Rights Israel said ambulances trying to take some of the critically wounded from Rafah to nearby Khan Younis, which has a larger hospital, were delayed at Israeli military checkpoints. The ambulances eventually were permitted to pass but were forced to take dirt roads.
The army said it was allowing safe passage of the ambulances.
The attack occurred about half a mile from Tel Sultan, which the army invaded Tuesday.
The massive invasion — the largest in the Gaza Strip in years — came less than a week after Palestinian militants killed 13 soldiers, including seven in the Rafah area.
Four people, including an unarmed 14-year-old boy, were killed in the neighborhood Wednesday before the protest. A day earlier, 20 Palestinians were killed in fighting. Palestinians said most of the casualties were civilians.
Israeli troops also stormed houses in Tel Sultan, confining tens of thousands of residents to houses without electricity or water.
The invasion knocked out power in the Rafah refugee camp, home to an estimated 90,000 people, local Palestinian officials said. By Wednesday, they said, there was no water service.
Palestinians accused the army of intentionally knocking out power to the camp, an accusation the army dismissed as "ludicrous." Army officials said they had restored power overnight and were working to resolve Wednesday's disruptions as well.
"There is no humanitarian crisis and we are not nearing the point where there could be a humanitarian crisis," said Lt. Col. Grisha Yakobowits, the army's humanitarian coordinator in the area.
The United Nations and European Union have demanded a halt to the invasion.
On Wednesday, Tel Sultan residents remained holed up in their homes as gunfire crackled in the air.
Salwa Abu Jazar, a 33-year-old mother of four, said her family got almost no sleep because of the sound of combat helicopters and shooting echoing through the camp.
"There is no water, no electricity, and it is very hard to move inside the house using candles because snipers in the building next door will shoot you," Abu Jazar said.
The fighting revived debate inside Israel on its continued presence in Gaza. Sharon has proposed withdrawing from the volatile area, but his Likud Party rejected the proposal earlier this month. Sharon has pledged to push forward anyway.
"This is a human and political tragedy that stems from our presence in Gaza. It clearly shows that this presence cannot continue," said Justice Minister Yosef Lapid of the centrist Shinui Party.
Early Wednesday, the army said it demolished the Rafah home of an Islamic Jihad militant it claimed was responsible for a shooting attack earlier this month that killed a pregnant Israeli settler and her four daughters. Palestinian witnesses said at least three homes were demolished overnight.
Ali Bayomi, a 55-year-old resident of Rafah, said soldiers arrested two of his cousins and were using them as human shields while searching homes. A military spokesman had no information on the incident, but said army rules prohibit the use of human shields.