Dozens of protesters have been arrested by riot gear-clad police in peaceful demonstrations in downtown Phoenix, capital of Arizona, on Thursday following an all-night vigil and prayer to mark the U.S. District Judge Susan Bolton's significant ruling putting on hold the most controversial parts of the draconian anti-immigration law.

Police arrest protestors during a demonstration against Arizona's controversial Senate Bill 1070 immigration law in downtown Phoenix, Arizona, the United States, July 29, 2010. The immigration law takes effect in Arizona on Thursday with some key portions blocked by U.S. District Court Judge Susan Bolton. [Qi Heng/Xinhua]

An aged woman protester was arrested after she engaged in a confrontation with scores of police officers in front of Wells Fargo building across the street from the Calvin C. Goode Municipal Building. The woman, who was in a yellow T-shirt, is a member of the Unitarian Universalist Association of Congregations, a national religious group based in Boston, Massachusetts, was arrested by police and taken into a waiting van.

The protests were peaceful but disruptive in several locations in the city. Hundreds of Senate Bill 1070 opponents blocked Washington Street near Phoenix City Hall for nearly an hour Thursday morning, snarling traffic and light-rail service.

At least two dozen including the aged woman whose identity could not be verified, were arrested at that location, after linking arms and lying down in the street, said Sgt. Tommy Thompson, a spokesman for the Phoenix Police Department. They were charged with obstructing a public thoroughfare, which is a misdemeanor, Thompson said.

Hundreds of emotional demonstrators from different groups across the country are staging a raucous and high-profile demonstration in downtown Phoenix, in support of U.S. District Judge Susan Bolton's ruling putting on hold some of the most controversial clauses of the Senate Bill 1070, demanding the stop of deportation of illegal immigrants and the equal representation of all races.

Many of the protesters arrived in Phoenix from California, Georgia and other states by buses and airplanes. Some of them have been here preparing for the event for days. They banged drums and chanted "Hey Ho, Hey Ho, SB 1070 has got to go," "Arrest Arpaio, not the people." A protester dressed as Joe Arpaio, Sheriff of Maricopa County, Arizona, who claimed himself to be "America's toughest sheriff," posed in confrontation with police officers. Arpaio has been harsh in dealing with criminals and illegal immigrants, and he has drawn the ire from the activists.