Israeli officials said that they were examining all the allegations, that they did not aim at civilians and that they were not certain that the source of fire that killed and wounded the United Nations drivers was Israeli.

Image Soldiers rested on the Israeli side of the border with Gaza during the three-hour cease-fire on Wednesday. Credit... Moises Saman for The New York Times

“We do our utmost to avoid hitting civilians, and many times we don’t fire because we see civilians nearby,” said Maj. Avital Leibovich, chief army spokeswoman for the foreign media. “We are holding meetings with U.N. officials to try to work out a mechanism so that their work can go forward.”

She said that the army learned of the Red Cross allegations in a media report, and that the Geneva-based committee had not yet presented the evidence of what she called “these very serious allegations” to the army.

At the United Nations, members of the Security Council voted Thursday night to approve a resolution calling for “an immediate, durable and fully respected cease-fire” that would lead to the “full withdrawal” of Israeli forces from Gaza, the passage of humanitarian aid to the Palestinians and an end to the trafficking of arms and ammunition into the territory.

Fourteen nations approved the measure, with the United States abstaining. Secretary of State Condoleezza Rice said the United States abstained from voting on the resolution, which left it unclear how a cease-fire would be enforced, because it wanted to see whether mediation efforts undertaken by President Hosni Mubarak of Egypt succeed. The United States did not veto the resolution because Washington supports its overall goals, she said.