UNITED NATIONS — Attacks against Israeli and U.N. targets in Lebanon — coupled with Gaza protesters shouting “death to America” — signaled Muslims’ hostility toward President Bush, who arrives in Jerusalem today for a week-long Middle East trip designed to promote peace talks. An American-born Qaeda figure, Adam Gadahn, last week called his organization’s followers to greet Mr. Bush “not with flowers or clapping, but with bombs and booby-trapped vehicles.” On Sunday, Iranian boats attempted to provoke U.S. Navy ships in the Strait of Hormuz. Similarly, yesterday’s incidents in Lebanon were seen as an attempt by Sunni and Shiite Islamists to serve as a contrast with Mr. Bush’s mediation between Israelis and Palestinian Arabs.

“Iran was a threat, Iran is a threat, and Iran will continue to be a threat if they are allowed to learn how to enrich uranium,” Mr. Bush told White House reporters yesterday.

He also called to make “outlines of a state clearly defined” so that “the Palestinians who agree that Israel ought to exist and agree that the state ought to live side-by-side with Israel in peace have something to be for.”

Heavy security arrangements in Jerusalem in preparation for today’s visit are expected to seriously disrupt life for local residents, who braced themselves for major traffic jams in the city. Mr. Bush is expected to meet President Peres today, as well as Prime Minister Olmert and other Israeli officials, before meeting the Palestinian Arab premier, Mahmoud Abbas. According to a report in the Jerusalem Post, Washington is considering a future deployment of foreign troops to guarantee security in the West Bank after Israel withdraws from most of the area as part of an agreement with Palestinian Arabs. But the experience that Israel has had with a U.N. force deployed in Lebanon after its 2006 war with Hezbollah — as exemplified by yesterday’s attacks — is mixed at best.

The U.N. Interim Force in Lebanon needs to be “more proactive and take further action to prevent such future attacks,” the officer in charge at Israel’s mission to the United Nations, Gilad Cohen, wrote to Secretary-General Ban yesterday. “Israel holds the Lebanese government responsible,” he added, referring to the attack on the northern Israeli town of Shlomi, where two Katyusha rockets landed in the early hours of yesterday morning.

A U.N. spokeswoman, Michele Montas, said yesterday that Unifil has not completed its investigation and, more than 24 hours after the event took place, the U.N. force was unable to “confirm or deny that report about the rocket fire.”

A source close to Unifil said the rockets carried no explosive devices. Yesterday afternoon, two Irish U.N. peacekeepers, which were patrolling in the area during a mission of the U.N. Interim Force in Lebanon, were injured as their vehicle hit a roadside bomb, Ms. Montas reported.

Israeli analysts said the attacks were unlikely to have been carried out by the Iranian-backed Hezbollah, as the Shiite organization is in a rebuilding phase, trying to compensate for the losses it suffered in the war. Rather, they pointed to a Sunni Palestinian Arab faction affiliated with Al Qaeda.

The faction, known as Fatah al-Islam, recently fought the Lebanese army in the northern Lebanese Palestinian Arab refugee camp Nahr el-Bared. After losing there, some of the group top operators reportedly escaped to camps near the southern town of Sidon. The only other attack on Israel since the war, last June, was also ascribed to Palestinian Arab Sunnis.

In a Ynet article titled “Bin Laden spoils the party” — a reference to the Qaeda-affiliated group and Mr. Bush’s visit — the military analyst Ron Ben Yishai wrote that the type of rocket used in yesterday’s attack on Shlomi, and its light payload, indicated it was carried by a small group, most likely Fatah al-Islam, which struggles to avoid detection by Unifil or Lebanon’s army.

In Gaza city, meanwhile, thousands of protesters affiliated with the Islamic Jihad demonstrated yesterday, carrying signs calling for “death to Israel and America,” according to the French News Agency, AFP. “Bush, you will never halt the march of Islam,” the terrorist organization’s leader, Abdullahal-Shami, told the crowd. His people will fight “for the liberation of Palestine in its entirety,” he vowed.