But the Obama administration refused to endorse a statement that singled out Israel, and it proposed a broader condemnation of the violence that would include the assault by passengers of the Israeli commandos as they landed on the deck of the ship.

As the wrangling continued late Monday night and in the early hours Tuesday, the two countries were trying to work out their differences on the wording, including whether to specify that the investigation should be conducted by outsiders, diplomats said.

While condemnation of Israel in the Security Council is not uncommon, the criticism at the emergency session called by Turkey and Lebanon was notable for both its vehemence and for the broad array of countries demanding an independent investigation into the decision to fire on civilians in what they described as a humanitarian mission.

Foreign Minister Ahmet Davutoglu of Turkey, whose country’s once close relations with Israel have deteriorated markedly since Israel’s invasion of Gaza in 2009, called the attack “tantamount to banditry and piracy; it is murder conducted by a state.”

Noting that the ships were carrying items such as a playground equipment, cancer medicine and milk powder, he said that given the history of the Jews the Israelis should be more conscious than others of “the dangers and inhumanity of ghettoes as the one we currently witness in occupied Gaza.”

Gerard Araud, the French ambassador, said the death toll indicated “there was disproportionate use of force and a level of violence which nothing justifies and which we condemn.”

Nawaf Salam, the Lebanese ambassador, said even the laws of war require the delivery of humanitarian aid.