Gaza City Gaza Strip ? France and Egypt announced an initiative to stop the fighting in Gaza late Tuesday, hours after Israeli mortar shells exploded near a U.N. school sheltering hundreds of people displaced by the onslaught on Hamas militants. At least 30 Palestinians died, staining streets with blood.

The Egyptian and French presidents didn’t release details of their proposal, saying only that it involved an immediate cease-fire to permit humanitarian aid into Gaza and talks to settle the differences between Israel and the Islamic militants of Hamas who rule the small coastal territory.

They said they were awaiting a response from Israel. Israeli officials in Jerusalem declined immediate comment on the announcement, which came amid diplomatic efforts by the U.S. and other nations to resolve a conflict that has seen 600 people killed in 11 days.

Secretary of State Condoleezza Rice weclomed the initiative, but cautioned that no agreement would succeed unless it halted Hamas rocket attacks on Israel and arms smuggling into Gaza.

Earlier in the day, President-elect Barack Obama broke his silence on the crisis, saying that “the loss of civilian life in Gaza and in Israel is a source of deep concern for me.” He declined to go further, reiterating his stance that the U.S. has only one president at a time.

Israel’s military said its shelling at the school — the deadliest single episode since Israeli ground forces invaded Gaza on Saturday after a week of air bombardment — was a response to mortar fire from within the school and said Hamas militants were using civilians as cover.

Two residents of the area who spoke with The Associated Press by telephone said they saw a small group of militants firing mortar rounds from a street near the school, where 350 people had gathered to get away from the shelling. They spoke on condition of anonymity for fear of reprisal.

Majed Hamdan, an AP photographer, rushed to the scene shortly after the attacks. At the hospital, he said, many children were among the dead.

“I saw women and men — parents — slapping their faces in grief, screaming, some of them collapsed to the floor. They knew their children were dead,” he said. “In the morgue, most of the killed appeared to be children. In the hospital, there wasn’t enough space for the wounded.”

He said there appeared to be marks on the pavement of five separate explosions in area of the school.

An Israeli defense official, speaking on condition of anonymity because he was not allowed to make the information public, said it appeared the military used 120-mm shells, among the largest mortar rounds.

U.N. officials demanded an investigation of the shelling. The carnage, which included 55 wounded, added to a surging civilian toll and drew mounting international pressure for Israel to end the offensive against Hamas.