The United States privately has served warning to Iran of possible military action should the Tehran hostages face trial, in the first known US message clearly aimed at the country's clerical hard-liners.
This message contrasted with softer public statments by the Carter administration and was seen as reflecting a new, "two-prong" strategy to wind down the ordeal of 53 Americans held captive in an increasingly unstable Iran since last November.
The US warining was relayed earlier in June by a Western ambassador here, Iranian and diplomatic sources said, and also seemed to reflect increasing consultation and cooperation within a strained Western alliance over the hostage crisis.
As Tehran diplomats saw it, the revised US approach sought to reinforce relatively moderate Iranian President Abolhassan Bani-Sadr with a low-key public policy on the impasse, while quietly opening a communications link with the President's powerful fundamentalist rivals.
Central to this US strategy, these diplomats believe, is the assumption that the road to freedom for the hostages still may be a long one, and that any major diplomatic offensive shuld be held off until positive results were reasonably certain.
Thus, the US warning on the "spy trial," a move sought by at least some Muslim militants within Iran's Islamic Republic Party (IRP). The IRP commands the largest cohesive voting bloc in the country's new parliment, empowered by Ayatollah Ruhollah Khomeini to rule on the captives' fate.
Washington's word, passed by an intermediary who local diplomats say was chosen partly for his access to senior IRP officials, reportedly was that if a trial went ahead, US military action against Iran could "not be ruled out."
It remained unclear whether the warning would be heeded. Some Tehran analysts suspected that the ultimate arbiter on the hostage issue would be Ayatollah Khomeini himself. The Ayatollah has shown little urgency in reaching a peaceful compromise with a superpower he regularly attacks as the "great Satan."
"But our feeling has been the Bani-Sadr, however much he personally favors a resolution of the hostage problem, is still not strong enough on the home front to pull this off," commented one European diplomat.
"It does, therefore, make sense for Washington to expand its diplomatic focus beyond the President to other Iranian political forces."
Washington's apparent move toward this view is traced by Tehran diplomats to the days following the failed US attempt to rescue the hostages in April.
Since then, the diplomats said, US officials have intensified coordination with West European allies over the search for a gradual, negotiated resolution of the crisis. The lack of such coordination, particularly on the question of economic sanctions against Iran, had been a sore point for many West European officials and had contributed to strains within the Western alliance.
Among the indications that this has been changing is a reported meeting between US Secretary of State Edmund Muskie and a Eurpean ambassador back from Tehran after the unsuccessful rescue attempt.
"I think we are working somewhat better with Washington on this now," commented a European diplomat.
"The problem," he added, "is that the key to resolving this horror, to getting the hostages out, still rests with a country in open-ended revolution,"