Cuban President Fidel Castro said his island nation will remain a one-party state under a communist system "even if the Soviet Union should disintegrate," Cuba's official news agency reported Saturday.

"We have defended the ideas of the revolution here in very difficult conditions and we will continue defending them in spite of the campaigns and threats of the United States against Cuba," Castro was quoted as saying in a Prensa Latina dispatch monitored in Mexico City.The Cuban president's remarks came during a three-hour speech Friday night to mark the 30th anniversary of the Cuban victory over U.S.-trained and equipped anti-Castro exiles at the Bay of Pigs.

Castro said the crisis in the Soviet Union would affect Cuba's military strength at a time when "we need more arms than ever," to defend the island.

Castro said he did not rule out the possibility that the situation in the Soviet Union could deteriorate into civil war.

"The situation is still to be defined," he said. "No one knows what may happen. We hope for the best not only for our own interests, but for the interests of the whole world."

Cuba's economy, which receives about $5 billion yearly in Soviet aid, has been shaken by events in the Soviet Union and Eastern Europe.

Castro said Soviet oil deliveries had been reduced by 25 percent, and that Cuba was having difficulties getting parts that formerly came from Czechoslovakia, East Germany, Hungary or Bulgaria.

But the Cuban leader said plans in the tourism, industrial and pharmaceutical sectors were going well, and he announced a bumper sugar harvest of 7.2 tons.

Socialism in Cuba "will make no concession on principles," the Cuban leader said. "There will continue to be a single party, the Communist Party, which corresponds to the current revolutionary stage of the country."

Castro also said Cuba would continue the system of centralized economic planning.

He also warned about the negative consequences for the world if the Soviet disintegrates, the agency said.

"He recalled that the mere existence of the Soviet Union was a brake on imperialism's longings for domination and aggression," Prensa Latina said.

The Cuban leader's speech in the Karl Marx Theater in Playa Giron was "interrupted on a number of occasions by ovations and cheers from the audience," which included veterans who fought the CIA-trained exiles 30 years ago, Prensa Latina said.