PANAMA CITY, AUG. 4 -- Government agents today raided the headquarters of the Panamanian opposition movement that has orchestrated two months of protests demanding the ouster of military strongman Gen. Manuel Antonio Noriega.

The raid on the headquarters of the National Civic Crusade was conducted by officials from the attorney general's office, accompanied by armed security agents in civilian clothes. The agents searched files and hauled away boxes of documents, opposition workers said.

The raid took place at the Panamanian Chamber of Commerce, which has served as headquarters for the National Civic Crusade, a coalition of more than 100 professional and business groups opposed to the military-backed government.

Federal Prosecutor Mario Ballesteros told reporters after the raid that he was carrying out a legal order to search for "flyers posing a threat to state security" that had been printed and distributed by the organization. He said the flyers had been found and confiscated but declined to describe them.

Despite a driving rain, hundreds of opposition movement supporters gathered outside the building, taunting security agents and hurling rocks at a van used to cart away material seized in the raid.

An angry crowd later surrounded Ballesteros and his aides as they walked the two blocks back to their offices. Ballesteros was struck by a rock as the crowd chanted "murderer" and "justice."

Everyone inside the building was released after Ballesteros completed a three-hour search.

A second business organization, the Panamanian Association of Executives, was raided at the same time but nothing was confiscated, Ballesteros said.

Rafael Zuniga, executive director of the Chamber of Commerce, said agents confiscated the organization's stationery, minutes of meetings and lists of the names and telephone numbers of members and of foreign journalists.

Zuniga said the authorities also took flyers calling on Panamanians to join a major protest rally scheduled for Thursday. Workers who called out to reporters from an upper-story window said about 40 people, including more than a dozen students, were detained inside the building.

Some of the students who had been held inside the building said they were questioned about why they were there. They were photographed and their bags were searched, they said.