SAN FRANCISCO — A federal judge in San Francisco extended a restraining order on Monday that blocks an anti-abortion group from releasing any recordings that it secretly gathered at annual meetings of an abortion providers’ association.

U.S. District Judge William Orrick sided with claims by the National Abortion Federation and its members that they would suffer harassment, intimidation and even violence if the Center for Medical Progress was permitted to circulate the material.

The center last month released secretly recorded videos that it claimed showed Planned Parenthood employees selling fetal tissue for profit, which is illegal.

The federation, a professional association that represents clinics, health centers, doctor’s offices and hospitals where abortions are performed, alleges that officers with the Center for Medical Progress infiltrated the federation’s yearly conferences in Baltimore and San Francisco by posing as fetal tissue buyers.

Orrick initially issued a temporary restraining order on Friday prohibiting the center from releasing recordings, names, addresses or dates from the meetings.

The federation is seeking an injunction permanently disallowing release of the information.

It has sued the Irvine, California-based Center for Medical Progress and its officers claiming conspiracy, fraud, racketeering, misrepresentation and trespassing over what it alleges was a scheme to discredit and endanger federation members.

The lawsuit filed Friday claims that the center’s officers along with hired actors gained entry to the professional conferences attended by hundreds of doctors, counselors, abortion rights activists and clinic administrators by creating a phony tissue-procurement company called Biomax Procurement Services.

At the 2014 conference in San Francisco, Biomax representatives signed a security agreement required of all participants pledging not to record the event or disclose any information shared there, the lawsuit states.

David Daleiden, a leader of the Center for Medical Progress who is also named in the suit, said last week that Planned Parenthood and its allies were trying to silence the group and suppress investigative journalism.