MARSEILLES, France -- The French government feared Islamic terrorists would blow up a hijacked Air France passenger jet in the skies over Paris in a suicide operation, Interior Minister Charles Pasqua said Tuesday.


"We learned of it notably by an anonymous call received at the French Consulate in Oran," Pasqua said of the northwest Algerian port city.


"The hostage-takers were obviously not concerned about their lives or those of the passengers," Pasqua said, a day after French commandos freed 171 hostages aboard the jetliner that had been commandeered in Algiers on Christmas Eve.


The Islamic radicals who hijacked the plane were overheard saying they planned to blow the jetliner up in mid-flight over Paris, passengers held hostage aboard the plane said Tuesday.


Their revelations came the same day investigators discovered two caches of dynamite rigged with detonators hidden under two seats in the aircraft. French commandos stormed the plane Monday in an assault that killed all four hijackers.


"They demanded 27 tons of kerosene to fly to Paris, which wasn't necessary," passenger Ferhat Mehenni told the television network TF-1.


Only 10 tons of kerosene is necessary to make the trip to Paris, regional Prefect Hubert Blanc said Monday.


The extra kerosene, which jets use as fuel, would have caused a bigger fire if the plane did indeed crash.


"Their idea was to set Paris ablaze," said Mehenni, a well-known singer in Algeria. "They whispered it among themselves, and passengers overheard them."


Another unidentified passenger told the network that "They said they wanted the kerosene to fly to Paris and blow the plane up either over Orly (Airport) or over Paris."


Marseilles Police Chief Alain Gehin said he never heard the hijackers express "the intention of transforming the plane into a flying bomb" and detonating the explosives while in flight.


"But throughout our dialogue, it was understood that I could not take the risk of allowing a plane to take off that could be susceptible to being blown up in the air," Gehin said.


Gehin's acknowledgment that he would not allow the plane to leave could explain the timing of the assault on the plane at the Marseilles airport.


The hijackers had demanded to be flown to Paris by 5 P.M. Monday or they would kill a fourth hostage. They executed three in Algiers over the Christmas weekend.


When the deadline passed and French authorities were still trying to negotiate, the air pirates fired gunshots at the airport's control tower, shattering a window and apparently provoking the assault.


French commandos moved in, liberating 171 hostages and killing the hijackers in one of the most successful anti-terrorist operations in aviation history.


In Algeria, four Catholic priests including three Frenchmen were shot to death Tuesday in Tizi-Ouzou, about 100 kilometers east of Algiers.


The gunmen escaped. There was no claim of responsibility.


Monday's commando rescuers were lauded as national heros, and President Fran?ois Mitterrand expressed "the nation's gratitude."


Prime Minister Edouard Balladur basked in the glory of the successful rescue operation, seen as a boost to his expected presidential bid in the spring. He visited wounded passengers and commandos Tuesday in a Marseilles hospital.