Protesters gathered in cities around the world Friday to mark six years since the first prisoner was transferred to the U.S. naval base at Guantanamo Bay, Cuba, as part of the country's so-called war on terror.

Donning orange jumpsuits mimicking those worn by detainees, a group in Rome picketed outside the U.S. embassy with signs calling for the end to illegal imprisonment.

Protesters, dressed variously as guards and prisoners, demonstrate outside the U.S. embassy in London in a call for the closing of the U.S. prison in Guantanamo Bay.
(Sang Tan/Associated Press)

It was among the first of many worldwide demonstrations planned by Amnesty International and culminating in Washington.

Other cities holding protests included Brussels, Istanbul and Manila.

In London, protesters took turns sitting inside a "replica Guantanamo cage" during an all-night vigil in front of the U.S. embassy, Amnesty said.

The protesters are calling for the closure of the high-security prison facility, which houses some 275 people suspected by the United States of having links to al-Qaeda. One Canadian, Omar Khadr, is imprisoned there.

The U.S. began shipping prisoners to Guantanamo Bay in the aftermath of the Sept. 11, 2001, hijackings, turning the naval base into a highly secure prison camp.

Elsewhere on Friday, hundreds of people wearing white face masks and orange overalls in Sydney, Australia, protested in the city's central business hub.

Australia is home to the only prisoner ever convicted through the Guantanamo military tribunals, but that case was the result of a plea bargain.

After five years in the U.S. facility, David Hicks admitted in early 2007 to fighting alongside al-Qaeda and providing material support to the Taliban. He was then sent to Australia to serve a nine-month sentence that ended in late December 2007.

His father, Terry Hicks, addressed a rally in Adelaide, Australia, on his behalf, saying they share the same view: "The best thing is to shut the place."

Some 500 Guantanamo prisoners have been released or transferred to other governments. 

The family of the lone Canadian in the facility, 21-year-old Khadr, resides in Toronto.

He was taken into custody in 2002 when, at age 15, he was accused of throwing a grenade during a firefight in Afghanistan that killed a U.S. soldier.