Statements by Presdent Carter and his senior congressional aide, Frank Moore, were the subjects of controversy yesterday as the presidential campaign entered its final phase amid an unusually volatile international climate.

Carter, in his Tuesday night debate with Republican presidential nominee Ronald Reagan, explicitly declared that the United States would "make delivery" on several hundred million dollars of military spare parts and other equipment to Iran if the American hosages are released safely. It had been understood by all sides in the past that Iran would get the spare parts if the United States gets the hostages, but in recent days the administration had avoided saying so in order to foretall domestic as well as international complications.

State Department spokesman John Trattner, under a hail of press questioning, declined to amplify or explain the president's stand due to the "immensely difficult and tangled situation" between the United States and Iran at the moment.

Adding to the tangles was an interview published in yesterday's Shreveport Journal in which Moore was quoted as saying that Irans leader, Ayatollah Ruhollah Khomeini, "has cancer of the colon" and is "not going to last long." rMoore was also quoted as saying that in the event of the religious leader's death, U.S. leaders expect a coalition of present and former military leaders to take power in Iran.

Additional international suspense and complexity, if any more were possible, is emerging in the increasingly unpredictable situation in Poland. That country's two top leaders were summoned to Moscow yesterday, in the latest in a series of developments adding to concern in Washington about the possibility of an internal showdown -- which could possibly bring in Soviet troops -- in the near future.

Administration officials dealing with Iran were alarmed by the Moore remarks, which could be seized upon by elements in the political structure there which are fighting a last-ditch battle against the return of the hostages. This apprehension was heightened by the extremely delicate stage of decision-making by the Iranian Majlis, or parliament, which is expected to meet in public session in Tehran today for debate on the hostage issue.

The White House, shortly after reading press service accounts of the Moore interview, issued a three-part denial. The chief of White House congressional relations is "not a spokesman" for the administration on Iran affairs; the administration has "no information" suggesting that Khomeini is terminally ill; and as a matter of policy the the administration does not speculate on internal developments in Iran, the White House statement said.

Officials said they had no authoritative information from Iran about the upshot of the closed parliamentary sessions which have been taking place since last Sunday in Tehran to determine the conditions for the hostage release. It is considered quite possible and by some estimates even likely that the Majlis will decide before Election Day Nov. 4 on Iran's official demands -- but this could still leave further steps to be taken before the Americans return from their long ordeal.

There is no indication from Tehran that the Majlis has decided on the means by which its terms could be implemented -- and thus release of the hostages accomplished -- when and if they are announced. Someone or some authority will have to decide whether the conditions have been met, except in the less likely case that the parliament takes this upon itself.

While public remarks by several political leaders in Tehran suggest that Iran's demands will conform closely to four conditions set out by Khomeini on Sept. 12, these are yet to be set forward in practical detail or established officially. Thus there is some chance that Iran's conditions could turn out to be difficult or even impossible for the United States to meet.

Carter, in this situation, may be required to declare himself formally on Iran's conditions on the very eve of the presidential voting, with the fate of the hostages as well as the good name and national interest of the United States in the balance. In what seemed to be an effort to lay the groundwork, Carter made a point of saying on the campaign trail yesterday that the U.S. posture on the benefits to Iran of releasing the hostages has not changed since early this year.

One thing that has changed in the meantime, of course, is that Iran is now at war with Iraq in a Persian Gulf conflict which holds grave dangers for the world's oil supplies, and in which the United States has declared its neutrality. For this reason it is far more complicated now to lift the U.S. embargo on the dispatch to Iran of about $400 million in missiles, spare parts and other military equipment which was ordered and paid for before the hostages were seized.

In an effort to defuse criticism of this potential military supply to Iran in the midst of the war, high administration officials in recent days have declined to say explicitly what the United States would do about the shipments. Vice President Walter Mondale last Sunday on "Face the Nation" (CBS, WDVM), for example, said, "We have not had to, nor should we at this point, in my opinion, face up to the questions of spare parts."

Faced with the switch in signals brought about by the president's "make delivery" remarks in the debate with Reagan, the State Department was forced into a public defense of he principle of supplying the military gear.

Spokesman Trattner said the United States can maintain its impartiality in the Persian Gulf war because the military gear was in the supply pipeline before the war, rather than being a "resupply" initiated after the start of hostilities. He extended the same distinction to Soviet military supplies, indicating that the United States would not object to Russian dispatch to its client, Iraq, of supplies which had been ordered before the fighting started.