The Carter administration issued another warning to Iran yesterday, strongly suggesting that the United States will undertake a series of punitive measures that may include military movements if the American hostages are subjected to "public expolitation" before an international tribunal.
The warning was delivered by White House press secretary Jody Powell, who said the United States would consider it a "further provocation" if Iranian authorities go through with threats to bring the 50 hostages before an international tribunal that would convene to investigate "American crimes" against Iran.
"The United States is seeking a peacful solution through every available channel," Powell added. "This is far preferable to other remedies that are available to the United States."
The language of the warning was almost identical of a White House statement issued Nov. 20 in response to Iranian threats to try the hostages as spies. It appeared to be aimed at forcing Iran to back down on its threat to convene a tribunal, much as Iran earlier backed down from the threat of spy trials.
The White House effort to influence the decisions of Iranian authorities came as, independently, the administration continued moving toward steps with U.S. allies to increase economic pressure on Iran.
Officials suggested that some of these measures could become known in a few days and would not necessarily hinge on first obtaining a U.N. Security Council resolution calling for economic sanctions against Iran.
Powell would not discuss specific actions the administration is considering should the hostages be brought before a tribunal. He also said that the president remains committed to the promise he made to the families of the hostages that he will order no action that would cause bloodshed so long as the hostages are not harmed physcially.
That would seem to rule out U.S. military raids on Iran in response to a convening of an international tribunal. But what has not been ruled out, and is known to be under consideration as an option is a more measured response involving military forces, for example a naval blockade.
The United States has two large naval task forces in the Arabian Sea that have the ability to shut off access to Iran from the sea.
However, such a military move, though short of open warfare, would involve grave risks and is considered by informed sources to be one of the administrtion's "outer options," to be imposed depending on the degree of effectiveness of nonmilitary measures and the extent to which Iran "publicly exploits" the hostages.
While Powell would not discuss specifics, he reiterated that the longer the hostages are held "the higher the price" Iran will have to pay because of U.S. retaliation. This was clearly meant to convey U.S. intentions to step up international economic pressure on Iran, leading, if necessary, to military steps short of warfare, such as a blockade.
On another front, Donald McHenry, U.S. ambassador to the United Nations, yesterday began sounding out other Security Council members on the chances of a sanctions resolution that would provide a basis for concerted economic pressure on Iran by the United States and its principal European allies.
The possibility of seeking U.N. economic sanctions has been under active consideration by the Carter administration since last week when Secretary of the State Cyrus R. Vance conferred with the leaders of Britian, France, West Germany and Italy about their willingness to cooperate in joint retaliatory measures.
Specifically, the United States wants the Europeans to help block Iranian efforts to get around the squeeze imposed on the Iranian economy by the freezing of more than $8 billion n Iranian government assets held by U.S. banks and their foreign subsidiaries.
The freeze, which has tied up roughly half of Iran's hard currency foreign reseves, has made it difficult for Iran to obtain essential imports. Its former large-scale trade with the United States has been almost totally cut off and its efforts to find other suppliers have been greatly hampered by unwillingness to sell goods to Iran without guarantees of payment.
Before Vance's European visit, the United States had started to detect signs that some big international banks haedquartered in Western Europe and Japan were beginning to move into the void with offers to provide financing and other services necessary to guarantee payment for imports.
Vance's mission was to ask West European governments to plug such potential escape routes for Iran by putting pressure on their banks and exporters not to deal with the Iranians.
The Europeans, while expressing willingness to cooperate in some degree, reportedly told Vance that it would be easier for them to take the necessary steps if they were able to operate under the mandate of a U.N. sanctions resolution.
Otherwise, they are understood to have said, restrictions imposed on them by their respective national laws and by the political power of their domestic business communities would lessen the amount of leverage they could bring to bear on private banks and businesses.
That point was underscored yesterday by British Prime Minister Margaret Thatcher, who is on a U.S. visit. Although she reiterated her public pledge to support any U.S. effort to have sanctions imposed against Iran by the United Nations, she also said that britain "couldn't possibly" undertake an economic embargo without a U.N. seal of approval.
Under British law, special legislation is required for that country to participate in an exonomic boycott that does not have U.N. authorization, and British sources say it would be extremely difficult, if not impossible, to get such legislation through Parliament.
However, U.S. officials are keenly aware that getting Security Council approval of a sanctions resolution -- even a loosely worded one that does not seek a total cutoff of trade and financial dealings with Iran -- will require very delicate and probably lengthy negotiations.
To get a resolution passed, the administration will need support from nine members of the 15-nation council and will have to win agreement from the Soviet Union not to kill the move with a veto. Diplomatic sources said yesterday that continued uncertainty about Washington's ability to overcome these two problems stands in the way of a formal decision to ask the council for sanctions.
A Soviet response on its intentions about using its veto is expected when Ambassador Anatoliy F. Dobrynin, in Moscow for consultation, return to Washington. So far, though, the Soviets have not indicated when Dobrynin will be back.
In the meantime, the sources said, McHenry has been ordered to start sounding out Third World members of the council on their views. But, they added, the talks are being conducted in a preliminary, low-key manner for now.