Updated

Hundreds of anti-war demonstrators listened Saturday to South Africa's Bishop Desmond Tutu speak at a church across from the United Nations before joining thousands more in the streets to protest possible U.S. military action in Iraq.

"Peace! Peace! Peace! Let America listen to the rest of the world — and the rest of the world is saying: `Give the inspectors time,"' Tutu told the Christians, Jews, Muslims and Buddhist monks who filled the ecumenical service.

Outside, protesters filled at least nine blocks of First Avenue, starting about five blocks to the north, and organizers were hoping to attract 100,000 people in opposition to war.

Demonstrations and protest marches against the war drew hundreds of thousands of people in cities around the world Saturday.

In Rome, many protesters displayed rainbow "peace" flags, while participants in Berlin marched through the streets to back the strong anti-war stance spearheaded by Chancellor Gerhard Schroeder. In London, protests hoped to increase the pressure on Prime Minister Tony Blair, who has been Europe's biggest supporter of the tough U.S. policy.

Anti-war rallies also were planned Saturday in U.S. cities including Chicago, Philadelphia, Miami and Seattle. Protesters in Detroit chanted "Give peace a chance."

"We need to leave Iraq alone," said rally organizer Kris Hamel of the Michigan Emergency Committee Against the War on Iraq.

In New York, the street demonstrators were kept several blocks north of the United Nations after city officials denied a permit to march along First Avenue past the U.N. complex, and a federal judge upheld the decision.

Security was extraordinarily tight, with the city on high alert for terrorist threats. Authorities deployed a new security "package" including sharpshooters and officers equipped with radiation detectors, hazardous materials decontamination equipment, bomb-sniffing dogs and air-sampling equipment able to detect chemical or biological weapons.

The heavy police presence and freezing temperatures did little to dampen the protesters' enthusiasm. Singer Richie Havens performed Woodstock anthem "Freedom," and Tutu, Harry Belafonte, Susan Sarandon, Pete Seeger and Danny Glover were expected to speak to the crowd.

"I came here for peace," said Minga Tshilembi, a native of the Congo. "I want to be together with everyone here, and to work with them."