PANAMA CITY, FEB. 29 -- A general strike called by opponents of Panamanian strongman Gen. Manuel Antonio Noriega started slowly today but appeared to be gathering strength by late afternoon, shutting down much of this capital's industry and roughly half of its commerce.

The strike was hastily organized by business and professional groups after the military-dominated regime controlled by Noriega deposed President Eric Arturo Delvalle Friday and installed a new figurehead civilian president. Delvalle, who unsuccessfully tried to fire Noriega as commander of the Panama Defense Forces, fled his home early Saturday and remained in hiding today to avoid expulsion from the country by the military.

According to Horacio Icaza, a director of the Panama City Chamber of Commerce and a member of the opposition National Civic Crusade, the strike closed about 70 percent of the industry and commerce in the capital. He said the strike was most successful in the industrial sector, with 90 percent adherence by members of the Union of Industrialists of Panama.

A diplomat estimated the strike was "roughly 65 to 70 percent effective" in the capital, with mixed results elsewhere around the country. She said the port city and free-trade zone of Colon was 60 percent closed, but that the Panama Canal was not affected by the strike.

Manuel Solis Palma, who was named acting president at the military's behest Friday to replace Delvalle, put the strike's effectiveness at only 40 percent in the capital and said public transportation, which is controlled by government supporters, functioned normally.

Solis Palma, who had served as education minister under Delvalle, told reporters at a central plaza that foreign governments would soon recognize him as Panama's president.

"We represent the constitutional order, and this situation is not understood because of the huge propaganda by the United States," Solis Palma said.

At about the same time as Solis Palma was appearing at a ceremony in a government building at the Plaza Porras, police arrested National Civic Crusade leader Aurelio Barria as he was trying to enter the nearby Chamber of Commerce building, which was closed by the military Thursday. Barria was held for about an hour and then released.

The strike, now set to end Wednesday, received backing from the country's two main opposition political leaders, Authentic Panamanian Party chief Arnulfo Arias and Christian Democratic Party President Ricardo Arias Calderon. They signed a statement of support in Miami yesterday, and it was distributed by followers late last night. Arias Calderon was refused reentry into the country from a trip abroad after Delvalle announced his abortive dismissal of Noriega.

Strike organizers acknowledged that the work stoppage started slowly because today was payday for many employees. Many shops and businesses opened in the morning to pay their workers, then closed later, strike organizers and merchants said.

Some shopkeepers interviewed in different parts of the city also said they felt threatened by warnings from the military that their stores might be looted by mobs if they went on strike.

"We wanted to close because we're against Noriega," said a shopkeeper selling beans and rice at a stall in the Public Market in the old quarter of Panama City. "But we were threatened that if we closed, people would come and rob us, so we stayed open."

A headline in the Noriega-controlled newspaper Critica warned today that a "business closed" is a "business seized." It quoted a leading civilian supporter of Noriega, Virgilio Perinan, as warning that hungry mobs could break into closed stores in search of food or medicine.

The strike appeared to be least effective on Central Avenue in downtown Panama City, where merchants said they remained open despite opposition to Noriega because they feared reprisals.

Luis Montezuma, 36, the assistant manager of a shoe store, called the warnings of mob action "a form of intimidation" by the Defense Forces.

"Eventually Noriega is going to leave because of the pressure, but now he has the power, so it's difficult," Montezuma said. "Panamanians don't want violence. We're looking for peaceful measures."

Across the street, a man in a tan uniform wrote down in a black notebook which shops were open and closed.

Nearby, a Noriega supporter expressed opposition to the work stoppage. "I see the strike as weak," said the man. Standing on a street corner holding a sign advertising a textile shop, he said he supported Noriega because he was "defending the sovereignty of the Panama Canal."