PHOENIX (AP) -- Arodi Berrelleza isn't one of the targets of Arizona's new law cracking down on illegal immigration - he's a U.S. citizen, a high school student from Phoenix.
But the 18-year-old said he's afraid he'll be arrested anyway if police see him driving around with friends and relatives, some of them illegal immigrants.
"If a cop sees them and they look Mexican, he's going to stop me," Berrelleza said. "What if people are U.S. citizens? They're going to be asking them if they have papers because of the color of their skin."
Berrelleza's concerns were echoed by Hispanics across the state Saturday, a day after Gov. Jan Brewer signed a bill that requires police to question people about their immigration status - including asking for identification - if they suspect someone is in the country illegally.
The new law, which will take effect in late July or early August, was cheered by many, including Maricopa County Sheriff Joe Arpaio, whose tough crackdowns have made him a hero in the anti-illegal immigration community. He said it gives him new authority to detain undocumented migrants who aren't accused of committing any other crimes.
"Now if we show they're illegal, we can actually arrest them and put them in our jails," Arpaio said.
Current law in Arizona and most states doesn't require police to ask about the immigration status of those they come across, and many departments prohibit officers from inquiring out of fear immigrants won't report crime or cooperate in other investigations.
Now, police departments seen as weak on illegal immigration could face lawsuits. The new measure also toughens restrictions on hiring illegal immigrants for day labor and knowingly transporting them.
Arizona has an estimated 460,000 illegal immigrants and is the state with the most illegal border crossings, with the harsh, remote desert serving as the gateway for thousands of Mexicans and Central Americans.
Arpaio said he hoped Arizona's example coerces the federal government into acting. President Barack Obama called the new law "misguided" Saturday and instructed the Justice Department to examine it to see if it's legal, but also allowed that the failure to enact immigration reform at the national level left the door open to "irresponsibility by others."
"You're going to see a lot of interest with the politicians in Washington to get something done," Arpaio said. "Because I think they'll be afraid that other states will follow this new law that's now been passed."
Mona Patton, a 58-year-old real estate agent from Prescott, said she's proud of Brewer and the Legislature for trying to protect people from violent drug cartels.
"When Arizonans aren't safe then something has to be done. We've got to let law enforcement handle things," Patton said.
A handful of protesters lingered at the state Capitol Saturday morning, with a bigger rally expected to draw hundreds on Sunday afternoon. Opponents of the law also gathered in Tucson outside the campaign headquarters of U.S. Rep. Raul Grijalva, a Democrat who opposes the measure and said his staff has been flooded with phone calls, some from people threatening violence and shouting racial slurs.
Brewer has ordered state officials to develop a training course for officers to learn what constitutes reasonable suspicion someone is in the U.S. illegally.
Civil rights advocates vowed to challenge the law in court, saying it would undoubtedly lead to racial profiling despite Brewer's assurances.
Supporters dismiss concerns about racial profiling, saying the law prohibits the use of race or nationality as the sole basis for an immigration check. The measure's sponsor, Republican Sen. Russell Pearce, said opponents are using racial profiling as a cover for their true concern - deportation.
"This is not about profiling. They're worried about the laws being enforced," Pearce said.
Largely because of Arpaio's policies, Arizona was known for tough illegal immigration crackdowns even before Brewer signed the bill into law.
But Arpaio's jurisdiction is limited, and the new law will have its biggest impact in the rest of the state, where many police bosses have long resisted suggestions that their officers conduct day-to-day immigration enforcement, saying it would distract them from investigating other crimes and sow distrust among immigrants.
Immigrant advocates say the bill could worsen an already tenuous relationship between law enforcement and Hispanics in Arizona.
State Sen. Rebecca Rios, a Phoenix Democrat and fourth-generation Arizonan, said she's concerned about her 14-year-old son being harassed by police because of his brown skin, black hair and dark-brown eyes.
"I don't want my son or anyone else's son targeted simply because of their physical characteristics," Rios said. "There's no reason I should have to carry around any proof of citizenship, nor my son."
After Brewer signed the bill, a reporter asked if she knew what an illegal immigrant looks like.
"I do not know what an illegal immigrant looks like," Brewer said. "I can tell you there are people in Arizona who assume they know what an illegal immigrant looks like. I don't know if they know that for a fact or not."
But she said with the training being developed for police officers, "the law will be enforced civily, fairly and without discriminatory points to it."
Associated Press Writer Paul Davenport contributed to this report.