SAN FRANCISCO — A federal appeals court that is reviewing Arizona’s tough new immigration law appeared inclined Monday to permit Arizona to require police to investigate the immigration status of people they have legally stopped but also seemed ready to reject more punitive provisions giving the state enforcement powers.

A three-judge panel of the 9th Circuit Court of Appeals, meeting in San Francisco, appeared likely to rule that Arizona may require police in certain situations to investigate a person’s immigration status if there is reasonable cause to suspect that person had committed a crime. But the panel also seemed to agree with a lower court ruling that other provisions of Arizona’s law were “pre-empted” by the federal government’s sole authority to enforce immigration laws.

The court appeared likely to reject provisions that would make it a state crime for a person to not carry immigration papers and allows for criminal punishment of illegal immigrants who seek work in Arizona.

“This is going to be a mixed verdict,” predicted UC Hastings Law Professor David I. Levine, noting that the law may ultimately be rendered meaningless.

About 200 demonstrators turned up outside the court, with about half opposing the Arizona law and the others backing the legislation. Arizona Gov. Jan Brewer also attended the proceedings.

The 9th Circuit judges chosen randomly to hear Arizona’s appeal are John Noonan, an appointee of Ronald Reagan and a moderate; Richard Paez, a Bill Clinton appointee and the son of Mexican immigrants; and Carlos Bea, an appointee of George W. Bush who was born in Spain and once was ordered deported from the United States. Bea appealed and won.

A decision by the 9th Circuit panel could be appealed to a larger circuit panel and then to U.S. Supreme Court. The three-member panel’s ruling could come within weeks or months.