Baghdad, Iraq ? Tens of thousands of Shiites thronged a Baghdad slum Friday to show support for Hezbollah as Arab anger toward Israel mounted on the Muslim holy day. Such protests have even reached Saudi Arabia, where public discontent is rare.

In the most violent demonstration, about 100 people threw stones and a firebomb at the British Embassy in Tehran, damaging the building but harming nobody as they accused Britain and the United States of being accomplices in Israel’s fight against Hezbollah, a Shiite group in Lebanon that is backed by Persian Iran.

Even Sunni Muslim demonstrators took to the streets of Damascus, Cairo and Amman. But their numbers were dwarfed by the huge Shiite turnout in Baghdad, organized by anti-American cleric Muqtada al-Sadr.

Crowds of al-Sadr supporters from across Iraq’s Shiite heartland converged on the capital’s Sadr City district, chanting “Death to Israel, Death to America” in the biggest pro-Hezbollah rally since the conflict began July 12.

Demonstrators, wearing white shrouds symbolizing willingness to die for Hezbollah, waved the guerrillas’ banner and chanted slogans in support of their leader, Sheik Hassan Nasrallah.

“Allah, Allah, give victory to Hassan Nasrallah,” the crowd chanted before burning Israeli and American flags.

Organizers and local police said hundreds of thousands attended the rally, but the U.S. military later estimated the crowd at 14,000. Associated Press reporters at the scene thought attendance was at least in the tens of thousands during the high point of the march.

An Iraqi boy holds a portrait of Shiite cleric Muqtada al-Sadr and Hezbollah's Sheik Hassan Nasrallah. Thousands of Shiites filled the streets of Baghdad's Sadr City to attend a rally in support of Lebanon after Friday prayers.

The rally went off peacefully – a remarkable achievement in a city where bombings and shootings are an everyday occurrence. Sadr City is under the effective control of the cleric’s Mahdi Army militia, which maintains its own security network.

However, five busloads of Shiite demonstrators were ambushed late Friday southwest of Baghdad as they returned home from the rally, police said. Imam Ali hospital in Sadr City received 14 wounded from the attack, who told them that three others had been killed, Rasool Qasim al Zibon, director of the hospital’s media office, said.

At least five members of the Iraqi parliament from al-Sadr’s movement attended the Baghdad demonstration, but the cleric himself was not there, presumably because of safety concerns.

In Saudi Arabia, hundreds of Shiites, who make up about 12 percent of the predominantly Sunni country’s population, have marched during the last three days in al-Qatif municipality in the Gulf coast region.

Under the watchful eyes of anti-riot police during a demonstration Thursday, protesters chanted: “No Sunni, no Shiites, only one Muslim unity” while others waved posters of Nasrallah chanting “Oh Nasrallah, oh beloved one, destroy destroy Tel Aviv.”

Israel launched its military campaign after Hezbollah guerrillas captured two Israeli soldiers and killed three others in a cross-border raid. Saudi rulers issued a statement chastising the group for “uncalculated adventures,” and a popular Sunni cleric even issued a religious edict that Muslims disavow Hezbollah.

But with the death toll of Lebanese civilians now in the hundreds and some 1 million people displaced, the Saudi government has backpedaled on its stance, even allowing rare demonstrations in favor of Hezbollah.

Arab League Spokesman Hesham Youssef said in Cairo that Arab foreign ministers would have an emergency meeting Monday in Beirut “as a way to express the Arabs’ solidarity with the Lebanese people, of which they will discuss the standoff in Lebanon.”