BEIRUT, Lebanon -- With little sign that the departing Bush administration will press Israel to halt the ground invasion of the Gaza Strip, diplomats and political leaders throughout the Middle East and Europe scrambled to find ways to bring an end to the violence.

But as the weekend drew to a close, the diplomatic activity appeared to have made little progress.

The United States used its U.N. Security Council veto to block a cease-fire deal that did not include guarantees sought by Israel, and Europe and even some Arab states held back from applying strong pressure on Israel to end its escalating offensive against Hamas, which is widely perceived as a client of Iran and Syria.

"Part of this war is a regional contest between the camp of Syria and Iran and the camp of Egypt, Jordan and Saudi Arabia," said Paul Salem, a Beirut-based analyst at the Carnegie Endowment for International Peace, a Washington think tank. "The region is divided. There's a lot of regional diplomatic activity, but the region has no leadership."

Images of bloodied Palestinian civilians continued to spark anger and put pressure on world leaders, especially in the Middle East, where protesters have demanded that their governments take action.

Yesterday, tens of thousands poured into the streets of Istanbul, Turkey, and demonstrators clashed with security forces near the U.S. Embassy north of Beirut, following sometimes violent protests across the world Saturday.

Palestinian Authority President Mahmoud Abbas, a Hamas rival, is scheduled to travel to the U.N. headquarters in New York City today to press for a Security Council or General Assembly vote addressing the conflict.

Europe, home to large and sometimes restive Muslim minorities, attempted to step up diplomatic efforts. European Union foreign-policy chief Javier Solana, calling for a cease-fire in an interview with the British Broadcasting Corp. as he departed for a four-day trip to the Middle East, said Europe was ready to send monitors to Gaza to oversee a truce.

Russia and France, both veto-wielding members of the Security Council, called for a cease-fire, with French President Nicolas Sarkozy heading to the region.

Several of the most strident calls for an end to the Israeli offensive came from leaders of Arab and Muslim countries that have normal relations with the Jewish state. Prime Minister Recep Tayyep Erdogan of Turkey, Israel's most reliable ally in the Muslim world, shuttled from capital to capital to push for a peace deal after calling the Gaza offensive "a crime against humanity."

In a telephone call with Middle East envoy and former British Prime Minister Tony Blair, Jordanian King Abdullah II said the Israeli offensive was unacceptable. Egyptian President Hosni Mubarak's office issued a statement demanding that the international community "confront the humanitarian consequence of this aggression on the Palestinian people in Gaza."

But there were also signs that Arab states were reluctant to take serious actions to punish Israel. Egypt, which shares a border with the 150-square-mile enclave, continued to refuse to open the frontier to allow its 1.5 million residents to escape the fighting. Neither Turkey, Egypt nor Jordan raised the possibility of acceding to public demands to suspend relations with the Jewish state. And the Arab League so far has continued to remain divided over how to condemn Israel.

Analysts say the U.S.-backed Arab states, under popular pressure to speak and act forcefully against Israel, are eager nonetheless to see Israel weaken Hamas' rule over Gaza.

"What they want is to put an end to Hamas as a governing power," said Adnan Abu-Odeh, a retired former Jordanian envoy to the United Nations. "That's why they cut it off -- to weaken it."

Officials in the United States, Israel and Egypt describe Hamas and other militant groups in Gaza as Iranian-armed and -trained proxy forces that are part of Tehran's strategy for gaining leverage in its dispute with the West over its nuclear program increasing regional influence.

Iran's efforts since the conflict began nine days ago have not risen above rhetoric and diplomatic maneuvering. An envoy of Ayatollah Ali Khamenei, Iran's supreme leader, toured the region, meeting late Saturday with Hezbollah leader Hassan Nasrallah, whose group fought Israel to a standstill in a 2006 war in Lebanon that resembled the conflict in Gaza.

Iran and Syria were believed to have given the Shiite militant group logistical and intelligence support during the fighting in Lebanon, which shares a border with Syria. But the commander of Iran's elite Revolutionary Guard Corps suggested yesterday that Gazans, who lack an airport and are cut off from the world by the Israelis and Egyptians, were on their own.

"The nation of Gaza are warriors and are seasoned in the battlefield," Gen. Mohammad Jafari said, according to the official Islamic Republic News Agency. "The geography of Gaza is helping the people surrounded there to resist, and they do not need any weapons from outside. Their own homemade weapons are enough for resistance."