WASHINGTON (Reuters) - The Supreme Court refused on Monday to revive a controversial Illinois law that prohibited audio recordings of police officers acting in public places, a ban that critics said violated the First Amendment of the U.S. Constitution.

Without comment, the court on Monday let stand a May 8 ruling by the 7th U.S. Circuit Court of Appeals in Chicago that blocked enforcement of the law, which had made it a felony to record audio of conversations unless all parties consented.

In a 2-1 ruling, the 7th Circuit called the law "the broadest of its kind," and said it likely violated the free speech and free press guarantees in the First Amendment.

The office of Cook County State's Attorney Anita Alvarez, who had defended the law, said "we respect and accept the court's decision in this matter and we are continuing to review all legal options as the case proceeds in U.S. district court."

The law had been challenged by the American Civil Liberties Union of Illinois, which was pursuing a Chicago-area "police accountability program" and sought to preempt the government from interfering with its recording of police officers.

Writing for the 7th Circuit majority, Judge Diane Sykes said Alvarez staked out an "extreme position" in arguing that openly recording what police say on the job on streets, sidewalks, plazas and parks deserved no First Amendment protection.

Judge Richard Posner dissented, saying the ruling "casts a shadow" over electronic privacy statutes nationwide that require consent of at least one party to record many conversations.

"Privacy is a social value. And so, of course, is public safety," he wrote. "The constitutional right that the majority creates is likely to impair the ability of police both to extract information relevant to police duties and to communicate effectively with persons whom they speak with in the line of duty."

In her appeal to the Supreme Court, Alvarez said the 7th Circuit wrongly created a new First Amendment right that could impair all eavesdropping statutes and the ability of governments to conduct surveillance.

The case is Alvarez v. Connell et al, U.S. Supreme Court, No. 12-318.

(Reporting by Jonathan Stempel; Editing by Howard Goller and Jackie Frank)