Greek-US ties feel the strain. Greece cries `slander' and hints at retribution as Reagan warns Americans to avoid Athens airport

Only two weeks after what appeared to be the beginning of an improvement in Greek-US relations, a new crisis has exploded between the two allies. Greece has accused the United States of orchestrating an international slander campaign against it, following the hijacking of Trans World Airlines Flight 847 shortly after it left Athens airport last Friday.

Washington has severely criticized the security arrangements at Athens airport and warned Americans to avoid it. During a televised press conference Tuesday, President Reagan said that the United States would consider a ban on flights to Athens if Greece did not strengthen its antiterrorist measures.

If the crisis is not resolved soon and if Washington moves to block travel to Athens airport, Greece might retaliate by hindering or curtailing the operations of the US bases in Greece, say Greek and foreign diplomatic observers in Athens.

Greek Prime Minister Andreas Papandreou has often said he intends to close the bases after the current agreement expires in 1988. Greece receives $500 million in military aid each year from the United States, in part as compensation for the use of the bases.

Aside from the political consequences, a US move to block travel to Athens airport would deal a harsh blow to the Greek economy, which is heavily dependent on tourism. There has not yet been any indication of mass cancellations on flights to Athens, but some Greek political sources fear the travel advisory alone will reduce the number of arrivals in Greece this summer.

In a written statement, Greek Foreign Minister Ioannis Charalambopoulos said the ``slander campaign directed against'' Greece was ``unacceptable'' and that ``Athens wants to develop relations with all countries, including of course the United States, from where the campaign unfortunately originates.'' He added that ``if this polemic continues, its effects can only be negative.''

The Greek government pointed out that countries such as France and West Germany have not been criticized so harshly when hijackings have occurred on their soil.

On paper the security arrangements at Athens airport do not differ from those at other international airports in the West. Before boarding the TWA jet that was hijacked, passengers had gone through two security checks, including metal detectors. One was staffed by airport security, the other by TWA personnel.

Conversations with businessmen and diplomats who use the Athens airport frequently as well as with sources familiar with security revealed that most consider security at Athens airport technically as adequate as in other such facilities in other countries. But several asserted that the human dimension of security is lax in Athens.

``In most airports, security personnel are constantly alert, watching the crowd, looking for suspicious behavior. Here that element is totally lacking. They seem to go through the motions,'' a Western diplomat says.

Washington's tough stance toward Greece in this crisis seems rooted in larger concerns. In his press conference, Mr. Reagan said he expected Athens to show willingness to comply with existing bilateral and international agreements on hijacking and the handling of captured terrorists.

Several diplomatic sources here say Greece was hasty and self-serving in releasing the hijackers' accomplice in exchange for some of the Greeks and other passengers on Flight 847. These sources claim the hijackers wanted to get rid of some passengers anyway.

Washington has frequently accused Greece of being tolerant of terrorists. Some Western and Greek political observers say the Greek government looks the other way while terrorists use Greece as a base of operations or a transit point to other areas in the West.

Such suspicions are reinforced by Prime Minister Papandreou's warm relations with Libya, Syria, and the Palestine Liberation Organization.