Apparently emboldened by their success, insurgents promptly took aim at Japan, threatening in a Web site message to send "lines of cars laden with explosives" to kill its troops in Iraq if they did not leave.
More than 60 foreigners have been taken hostage in recent months, and there were fears that the action by the Philippines government would lead to more kidnappings and prompt members of the U.S.-led coalition to think twice about sending, or keeping, their soldiers in Iraq.
"The Filipino withdrawal tells the insurgents that they can continue to chip away at this coalition and make it a coalition of two (Britain and the United States)," said Richard Shultz, a professor of security studies at Tufts University.
Also Tuesday, the military said two U.S. Marines and two U.S. soldiers were killed in action in Anbar Province, a Sunni-dominated area west of Baghdad. The Marines were killed in separate incidents Tuesday while conducting "security and stability operations." One soldier was killed in action Monday and a second died Monday of wounds received in action.
Meanwhile, U.N. inspectors will return to Iraq in the coming days following an official invitation from the new government, the head of the U.N. nuclear watchdog agency said Tuesday. Mohamed ElBaradei, director-general of the International Atomic Energy Agency, told reporters in Cairo that Iraqi Foreign Minister Hoshyar Zebari had formally asked his agency to return.
In Baghdad, Filipino hostage Angelo dela Cruz was dropped off in front of the United Arab Emirates Embassy on Tuesday, a day after his government withdrew the last of the 51 troops they had stationed here.
"Angelo has become a Filipino 'everyman,' a symbol of the hardworking Filipino seeking hope and opportunity," Philippines President Gloria Macapagal Arroyo said during a nationally televised address. "Angelo was spared, and we rejoice," she said with a smile.
With more than 7 million Filipinos working overseas — 1.4 million of them in the Middle East — many people in the Philippines developed a personal connection to dela Cruz since he was first shown in a video aired July 7 surrounded by masked gunmen who kidnapped him near the city of Fallujah. That connection put intense pressure on Arroyo to secure his freedom.
Dela Cruz's family, and much of the Philippines, cheered his release.
His wife, Arsenia, burst into tears in neighboring Jordan, where she had been awaiting word of him.
Safely inside the Philippines Embassy in Baghdad, dela Cruz enjoyed beer with friends, including a fellow Filipino driver, around a table covered with plates of salad, rice and traditional Iraqi chicken.
Dela Cruz said his captors treated him well, and he thanked Arroyo for pulling out the troops. "I know that the Filipinos are all very happy about the decision of the president," he said.
The United States and Iraq have criticized the pullout, saying it would endanger others here.
"All of us know that if you appease terrorism, you will sooner or later fall victim to it or be taken over by it," Gen. John Abizaid, the top U.S. military commander in the Middle East, said during a visit to Bahrain.
Thousands of foreigners work in Iraq, for U.S. forces, in reconstruction efforts or as drivers hauling fuel and cargo for private companies.
Of those kidnapped in recent months, some escaped, many were released and at least three were beheaded in gruesome videos designed to spread fear.
A fourth video released last week showed a man, identified as Bulgarian truck driver Georgi Lazov, kneeling before armed men from the Tawhid and Jihad group of Jordanian militant Abu Musab al-Zarqawi. The Al-Jazeera television station, which declined to show the rest of the video, said it depicted his killing.
The group had threatened to kill Lazov and fellow Bulgarian Ivailo Kepov if the U.S. military did not release Iraqi detainees. Kepov's fate remains unknown.
Bulgaria — with a 480-member infantry battalion here — refused to withdraw, though it did urge Bulgarian truck drivers to stop making trips into Iraq. Bulgarian Foreign Minister Solomon Pasi suggested Monday that all countries adopt a common "code of behavior" for such hostage crises. "In these cases, cooperation is crucial," he said.
The kidnappings could cause problems for many governments, including Bulgaria, that sent troops here over the strong opposition of their citizens.
Spain withdrew troops after a Socialist election victory following a terrorist attack in Madrid. South Korea also faced pressure to cancel plans to send 3,000 troops here when one of its citizens, Kim Sun-il, a 33-year-old translator, was kidnapped and beheaded by militants.
Soon after dela Cruz's release, his kidnappers — the Khaled bin al-Waleed Corps — took aim at Japan, demanding it pull out 500 troops sent here for medical and reconstruction duty. Japan refused in April to withdraw after three Japanese were kidnapped by Iraqi insurgents. They were released unharmed.
"To the government of Japan: Do what the Philippines has done. By God, nobody will protect you and we are not going to tolerate anybody," the group said in the Web site statement. "Lines of cars laden with explosives are awaiting you; we will not stop, God willing."
The group also told Arab and Islamic governments not to send troops.
"We are warning you for the last time: We will hit with an iron fist all those supporting the Americans or (interim Iraqi Prime Minister Iyad) Allawi or his cronies."
Allawi had asked some Muslim countries to contribute troops, but so far none has come forward. Violence is a likely factor. Malaysian Prime Minister Abdullah Ahmad Badawi said he would not even send a planned medical team until "the situation is a little more stable."
Iraq's fledgling interim government relies heavily on the 160,000 coalition troops to fight the 15-month-old insurgency, which has used car bombings, assassinations, sabotage and other violence to try to create chaos and drive out foreign forces.