Nicaragua is seeking to obtain military aircraft from Czechoslovakia but has no firm plans yet to bring in either these or more advanced warplanes, Nicaraguan officials said today.

"It is not planned at this time that MiG airplanes will come, and it is not planned at this time that any other type of planes will come," Interior Minister Tomas Borge said at a news conference this afternoon.

The government has said previously that it would like to obtain Soviet-made MiG 21 jet fighter-bombers, but it has failed to get them after a year of trying. U.S. officials have suggested strongly that the United States would attack any MiGs that were delivered to Nicaragua, and diplomatic sources here have said that the Soviet Union did not want to send any MiGs because it did not want to anger Washington.

Chief military spokeswoman Lt. Rosa Pasos said Nicaragua was "arranging" to obtain L39 aircraft from Czechoslovakia, but she said that no date has been fixed for their arrival. L39s, which are smaller and less sophisticated than MiG 21s, often are used as military trainers but can be converted for use in combat. It was unclear whether the Czechoslovak government was resisting supplying the L39s to Nicaragua, or whether negotiations still were under way over terms for delivering them.

The government statements on the aircraft were triggered by news reports from the United States that radar gear for use with advanced aircraft had arrived recently at Nicaragua's Caribbean port of El Bluff. U.S. officials here said military equipment was being unloaded at El Bluff, but they said they were not sure what kind of equipment it is.

Special security procedures have been in effect at El Bluff since Sunday, and travelers need special permission to enter or leave the port, special correspondent John Lantigua reported from the port of Puerto Cabezas to the north.

Residents in the area said that one or two ships were unloading a special cargo at El Bluff and that the usual stevedores were not permitted to handle the cargo, Lantigua reported. One of the Interior Ministry's highest ranking security officers was in the area, he reported.

Nicaraguan military officials said that the cargo being unloaded at El Bluff was not planes, but they left open the possibility that it might be weapons of some type.

In another development, Interior Minister Borge said the CIA had paid thousands of dollars to a Nicaraguan Finance Ministry official for information without knowing that the official was working for Nicaraguan intelligence.

The CIA first contacted the double agent, Horacio Arguello, in late 1982 by means of diplomats from a European country that Borge declined to identify, he said. The CIA paid $2,000 a month into Arguello's Citibank account in Miami for an unspecified period, and offered to raise it to $3,000 a month if Arguello would leave Nicaragua and denounce the coming elections here as a fraud, Borge said.