SYDNEY, Australia — Anti-war demonstrators held rallies across the globe Saturday to protest the war in Iraq as campaigners marked the third anniversary of the U.S.-led invasion with a demand that coalition troops pull out.

Around 500 protesters marched through central Sydney, chanting "End the war now and "Troops out of Iraq." Many campaigners waved placards branding President Bush the "World's No. 1 Terrorist" or expressing concerns that Iran could be the next country to face invasion.

"Iraq is a quagmire and has been a humanitarian disaster for the Iraqis," said Jean Parker, a member of the Australian branch of the Stop the War Coalition, which organized the march. "There is no way forward without ending the occupation."

Opposition to the war is still evident in Australia, which has some 1,300 troops in and around Iraq. Visiting Secretary of State Condoleezza Rice was heckled by campaigners in Sydney this week, who said she had "blood on her hands."

In Tokyo, about 2,000 people rallied in a downtown park, carrying signs saying "Stop the Occupation" as they listened to a series of anti-war speeches, said Takeshiko Tsukushi, a member of World Peace Now, which helped plan the rally. Tokyo police were unable to immediately confirm the number in attendance.

"The war is illegal under international law," Tsukushi said. "We want the immediate withdrawal of the Self-defense Forces and from Iraq along with all foreign troops."

Japanese Prime Minister Junichiro Koizumi is a staunch supporter of the U.S.-led coalition in Japan and dispatched 600 troops to the southern city of Samawah in 2004 to purify water and carry out other humanitarian tasks. The Cabinet approved an extension of that mission in December, authorizing soldiers to stay in Iraq through the end of the year.

But public opinion polls show the majority of Japanese oppose the mission, which has been criticized as a violation of the country's pacifist constitution. Many say the deployment has made Japan a target for terrorism.

In Turkey, thousands gathered in Istanbul for protests Other protests were planned in the cities of Izmir, Trabzon and the capital, Ankara.

"Murderer USA," read a sign unfurled by a communist in Taksim Square in Istanbul.

Turkey is Iraq's northern neighbor and the only Muslim-majority member of the NATO military alliance. Since the war, support for the United States has plummeted in Turkey.

Demonstrations were also expected across Europe.

In London, Scotland Yard police headquarters said streets around Piccadilly Circus in the heart of the shopping and theater district would be closed as up to 100,000 people planned to march through the capital. Britain has about 8,000 troops in Iraq.