A lawyer for a Phoenix police officer told a federal court Thursday his client could be sued for racial profiling if he enforces Arizona's new immigration law. It is the first hearing in a series of legal challenges filed over the controversial crackdown which has divided law enforcement in the state and across the country.

Police officer David Salgado arrives at the courthouse in Phoenix. His legal challenge to Arizona's controversial immigration law drew both critics and supporters to the federal hearing. (Associated Press)

Officer David Salgado, a 19-year veteran of the Phoenix police department, could also lose his job if he fails to enforce the new law, his attorney said.

Arizona's statute requires an officer to verify the immigration status of a person stopped for other alleged crimes, if "reasonable suspicion" exists of illegal presence in the U.S.

But the law also empowers Arizona residents to sue an officer they believe isn't enforcing the law to the fullest extent.

"If he enforces the law, he can be sued. If he doesn't enforce the law, he can be sued" by a private citizen, said Stephen Montoya, the attorney for Mr. Salgado. His client "is caught between a rock and a hard place," he said.

Mr Montoya also argued that the law, which makes it a state crime to be in the U.S. illegally, usurps federal authority over immigration. "The state of Arizona cannot order its employees to violate federal law," he said.

Attorneys for Arizona Gov. Jan Brewer told the judge that the lawsuit, which was also filed by an advocacy group called Chicanos Por La Causa, should be dismissed because the police officer and the group have no valid claim of immediate harm and the state law doesn't trump federal immigration law.

Outside the courthouse, in 105-degree heat, about 50 protesters and supporters of the law gathered; police kept the two sides apart.

U.S. District Judge Susan Bolton did not rule on whether to dismiss the challenge or block the law from being enforced. Unless an injunction is issued by a federal judge, the law will go into effect on July 29.

Hearings on at least two of the six other lawsuits, including one filed by the Obama administration, are scheduled for next week. One of the six suits was filed by another police officer, Martin Escobar. Mr. Escobar, who patrols a heavily Hispanic enclave in Tucson, the state's second-largest city, claims in the lawsuit that he would lose the cooperation of Latino witnesses, which he said was a key to solving crimes.

Separately, two Arizona county sheriffs announced the establishment of a legal fund to raise money to defend themselves and their deputies against lawsuits.

In May, police chiefs from Phoenix, Los Angeles, Houston, Philadelphia and other large cities met with Attorney General Eric Holder to voice concern that the law will drive a wedge between police and immigrant communities, drain resources and undermine public safety. Legislators in several states have begun to draft laws similar to that of Arizona.

But some police officers and sheriffs in Arizona, the country's busiest corridor for human and narcotic smuggling, say the law gives them an additional tool to tackle illegal immigration.

Law enforcement officers, who can decide when to arrest or shoot someone, should also be trusted to enforce the new law without profiling based on race, said Pinal County Sheriff Paul Babeu, whose jurisdiction covers a vast area between the Mexican border and Phoenix. "I believe in my deputies' professionalism," he said.

Currently, only 11 Pinal County deputies are cross-trained under a federal program that empowers some local law enforcement to help identify illegal immigrants.

"Now, all 214 of my deputies will have the authority" to round up those suspected of being here illegally, Mr. Babeu said.

The offices of Sheriff Babeu and nearby Cochise County Sheriff Larry Dever are named in a lawsuit recently filed by the American Civil Liberties Union. On Thursday, they announced they had started a legal fund, with the support of a non-profit group, Legacy Foundation, to help defend them against lawsuits.

"People will be lining up to sue us for racial profiling," said Mr. Dever. "It's an insult to the rank-and-file deputies who know how to operate within the parameters expected of them."

Ms. Brewer has also hired a private attorney to represent her in the lawsuits.

Ms. Brewer has said racial profiling won't be tolerated. After signing the bill on April 23, she ordered the state's police training and licensing board to develop a program that sets standards for enforcement to prevent profiling.