Phoenix, Arizona - Over 20,000 people marched in the streets of Phoenix Saturday in the first mass mobilisation of the year, calling for an end to the criminalisation of undocumented immigrants and the passage of immigration reform legislation.

Arizona is considered ground zero for the immigration debate due to its severe anti-immigrant policies and the controversial figure of Maricopa County Sheriff Joe Arpaio, whose deputies conduct frequent immigration sweeps in Latino neighbourhoods.

"We're not going to allow him to continue to abuse us and treat us as if we were criminals, when we're workers," said Salvador Reza, an organiser for PUENTE, the movement behind the march. "The message is clear for the [Barack] Obama administration: You need to put a stop to Sheriff Joe Arpaio's circus."

The largest march to protest Arpaio's criminalisation of immigrants in the history of Arizona came on the heels of a grand jury criminal investigation led by the U.S. Department of Justice (DOJ) that is focusing on abuse of power by his office.

Arpaio is also the subject of a probe by another division of the DOJ on the use of racial profiling during his immigration sweeps.

The protest destination was a five-jail complex administered by Arpaio, including an outdoor jail known as "Tent City", where hundreds of immigrants have been detained.

Celia Alejandra Alvarez, 29, attended the march. She was among the women who had been incarcerated in the jail following one of the sheriff's raids of a landscaping business last February.

"The pain you live in there is shameful," said Alvarez in a speech outside the jail in front of thousands of people.

The American Civil Liberties Union (ACLU) filed a civil rights claim on behalf of Alvarez. She alleged deputies broke her jaw during her arrest and that she was denied proper medical care during the time she was detained.

Arpaio told IPS he wasn't concerned about the grand jury investigation or the protests.

"I started out doing my job on this illegal immigration and I'm still doing it. The U.S. government agreed - they gave me 160 officers. If you want to blame anybody, why not blame Homeland Security that gave me all of this authority," he said.

In February 2007, Arpaio signed a 287(g) agreement with Immigration and Customs Enforcement (ICE) that allowed his deputies to act as immigration agents and placed retainers on undocumented migrants entering his jail.

Secretary of Homeland Security Janet Napolitano took away his street enforcement powers under a new agreement signed three months ago, but activists argue the programme should have been completely revoked.

"The wheels of government are moving too slowly on this," said Reza. "They could come and take control of the jails and the sheriff's office until the grand jury is resolved. If they don't do that, the sheriff will continue to take advantage of people."

For the migrants who marched, the call for Arpaio to be removed from office went hand in hand with a call for immigration reform.

"It's enough of the raids. There's so many murderers and thieves, why doesn't he focus on catching them?" asked Rosa Delia Cruz, 55, whose son was arrested by a sheriff's deputy after a traffic stop on his way back from work, and then deported.

"My grandchildren are afraid of going to school. They tell my daughter, 'Mom, if that man [Arpaio] arrests you, where am I going to go?'" she added.

Jennifer Allen, executive director of the Border Action Network (BAN), a human rights organisation based in Tuscon, Arizona, said national immigration reform is the solution to put an end to Arpaio's anti-immigrant crackdown.

"This march is important, not just for Phoenix, but it's important for Arizona and the country as a whole. Because Arizona has been ground zero for anti-immigrant attacks at local levels, through our state legislature, to justify horrible policies for the rest of the country," she said.

The march had national support, with organisers and caravans coming from California, Illinois and Washington, D.C. It also drew the participation of celebrities like the singer Linda Ronstadt, a native Arizonan.

"Arpaio thinks law in general doesn't apply to him. It's just pathetic. He's supposed to enforce the law, not break it," said Ronstadt, who walked the entire three-mile march.

She said his actions are "criminalising people that normally wouldn't be interested in a life of crime in any way, shape or form."

"They're taking jobs that, by and large, Americans won't take. Americans aren't that interested in working 12-hour days under the blazing sun, picking lettuce or strawberries. So without Mexican labour, we can't get food on the table," she added.

A disturbance towards the end of the march ruined the peaceful protest for several immigrant families.

The Phoenix Police Department said that protesters started throwing bottles of water at police officers and assaulted a policewoman on a horse.

Witnesses said the officer threw pepper spray at the crowd, hitting marchers who weren't involved in the incident. Several children were among them.

"They come with the horse on us and used gas. My child couldn't breathe," said Rocío Medina. Her daughter got cuts in her arm after being pushed by people running away from the pepper spray.

The police arrested four people on charges of assault.

Organisers of the event said the disturbances were caused by individuals not associated with their movement.

"We don't want the actions of a very small number of people to overshadow a day that was about peace. We are asking for a full investigation into the incident, both with respect to the conduct of those who were accused of disrupting the march and the actions of the police," said Chris Newman, an attorney for the National Day Laborer Organising Network.

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