Thousands of people protesting a sweeping crackdown on illegal immigrants by an Arizona sheriff marched through Phoenix on Saturday, toting placards reading "We Are Human" and "Stop the Raids."

Maricopa County Sheriff Joe Arpaio has dispatched deputies into Hispanic communities in the Phoenix area where they stop people and arrest anyone who cannot prove he or she is a legal U.S. resident.

Under a deal allowing them to enforce federal immigration laws, the deputies have arrested more than 1,500 people whom they determined were in Arizona illegally.

Latino activists and lawmakers call his program a clear case of racial profiling because only people who look Hispanic are targeted. Arpaio steadfastly denies the charge.

Earlier this month, he stirred more controversy when he marched 220 illegal immigrants in shackles and striped prison garb through Phoenix under armed guard.

"Walking people through the streets in chains, public shaming, it's medieval," said Veronica Perez, 32, an archeologist carrying signs reading "No Human Is Illegal" and "Stop the Raids."

"Isn't cruel and unusual punishment against the U.S. Constitution?" she asked.

The event was organized by activists from the National Day Laborer Organizing Network and a group called El Puente Arizona. Estimates of the number of participants ranged from 1,000 to 3,000.

Preparing for the march at a park in central Phoenix, school district coordinator Sylvia Airington, 47, slammed Arpaio's policies.

"Racial profiling, targeting the Hispanic community -- it's an embarrassment to America," she said.

What to do about an estimated 12 million illegal immigrants in the United States is an explosive political issue. But it has largely dropped out of the debate as concerns turn to the economic crisis.

A bid to push comprehensive immigration reform through Congress was rejected by Republican lawmakers two years ago. President Barack Obama, who supported the measure, has yet to address the matter.

"I voted for Obama for change," said welder Oscar Camacho, 45. "But with respect to immigration, I see no change at all."

Around 100 counter-demonstrators waving American flags turned out to support Arpaio on Saturday. Some carried holstered pistols.

"He is the only one to uphold illegal immigration laws," said Dina Rose, 52, standing on sidewalk by the sheriff's office in downtown Phoenix. "The county sheriff is America's last hope of protecting our freedoms."