he protests came as a suicide truck bomber killed at least five police officers Monday at a checkpoint west of Baghdad, said Iraqi police.

Journalist Muntadhar al-Zeidi, who was kidnapped by Shiite militants last year, was being held by Iraqi security Monday and interrogated about whether anybody paid him to throw his shoes at Bush during a press conference the previous day in Baghdad, said an Iraqi official.

He was also being tested for alcohol and drugs, and his shoes were being held as evidence, said the official, speaking on condition of anonymity because he was not authorized to talk to the media.

Showing the sole of your shoe to someone in the Arab world is a sign of extreme disrespect, and throwing your shoes is even worse.

Newspapers across the Arab world on Monday printed front-page photos of Bush ducking the flying shoes, and satellite TV stations repeatedly aired the incident, which provided fodder for jokes and was hailed by the president's many critics in the region.

"Iraq considers Sunday as the international day for shoes," said a joking text message circulating around the Saudi capital Riyadh.

Palestinian journalists in the West Bank town of Ramallah joked about who would be brave enough to toss their shoes at Secretary of State Condoleezza Rice, another U.S. official widely disliked in the region.

Many users of the popular Internet networking site Facebook posted the video of the incident to their profile pages, showing al-Zeidi leap from his chair as Bush and Iraqi Prime Minister Nouri al-Maliki were about to shake hands Sunday and hurl his shoes at the president, who was about 20 feet away. Bush ducked the airborne footwear and was not injured in the incident.

"This is a farewell kiss, you dog," al-Zeidi yelled in Arabic as he threw his shoes. "This is from the widows, the orphans and those who were killed in Iraq."

Al-Zeidi was immediately wrestled to the ground by Iraqi security guards. The incident raised fears of a security lapse in the heavily guarded Green Zone where the press conference took place. Reporters were repeatedly searched and asked to show identification before entering and while inside the compound, which houses al-Maliki's office and the U.S. Embassy.

Al-Zeid's tirade was echoed by Arabs across the Middle East who are fed up with U.S. policy in the region and still angry over Bush's decision to invade Iraq in 2003 to topple Saddam Hussein.

The response to the incident by Arabs in the street was ecstatic.

"Al-Zeidi is the man," said 42-year-old Jordanian businessman Samer Tabalat. "He did what Arab leaders failed to do."

Hoping to capitalize on this sentiment, al-Zeidi's TV station, Al-Baghdadia, repeatedly aired pleas to release the reporter Monday, while showing footage of explosions and playing background music that denounced the U.S. in Iraq.

"We have all been mobilized to work on releasing him, and all the organizations around the world are with us," said Abdel-Hameed al-Sayeh, the manager of Al-Baghdadia in Cairo, where the station is based.

Al-Jazeera television interviewed Saddam's former chief lawyer Khalil al-Dulaimi, who offered to defend al-Zeidi, calling him a "hero."

In Baghdad's Shiite slum of Sadr City, thousands of supporters of radical Shiite cleric Muqtada al-Sadr burned American flags to protest against Bush and called for the release of al-Zeidi.

"Bush, Bush, listen well: Two shoes on your head," the protesters chanted in unison.

In Najaf, a Shiite holy city, some protesters threw their shoes at an American patrol as it passed by. Witnesses said the American troops did not respond and continued on their patrol.

Al-Zeidi, who is in his late 20s, was kidnapped by Shiite militias on Nov. 16, 2007, and released three days later. His station said no ransom was paid and refused to discuss the case.

Violence in Iraq has declined significantly over the past year, but daily attacks continue to occur. The truck bomb that killed five police officers Monday also wounded 13 others, said Iraqi police. Hours earlier north of Baghdad, a female suicide bomber knocked on the front door of the home of the leader of a local volunteer Sunni militia and blew herself up, killing him, police also said.

Abdul-Zahra reported from Baghdad and Sinan from Cairo, Egypt. Associated Press writers Muhieddin Rashad in Baghdad, Mohammed Daraghmeh and Diaa Hadid in Ramallah, West Bank, Jamal Halaby in Amman, Jordan, and Donna Abu-Nasr in Riyadh, Saudi Arabia, contributed to this report..