Some of the American hostages in the occupied U.S. Embassy here still display open defiance of their Islamic student captors after more than seven weeks of imprisonment under armed guard, an American minister who visited them said tonight.

The Rev. William M. Howard Jr., one of three American clergymen who conducted Christmas services inside the embassy, said some of the captives showed their refusal to submit by saying "snappy things" to their guards.

His observations, relayed on the eve of his return to the United States along with his two colleagues seemed to indicate that resistance remained firm for at least some of the hostages inside the embassy although they have been under armed guard since Nov. 4.

As an example, Howard said he heard one of the prisoners mutter in the direction of the student guard, "What do you guys know?" Another hostage, advised that he could not discuss political subjects, asked about which football teams are playing in the Rose Bowl this year and added sarcastically, "Or is that too political for you?"

"About 10 were clearly rebellious" among the 21 hostages Howard saw during his overnight stay in the embassy, he said.

Meanwhile, in Washington, the State Department said today it is unable to account for the discrepancy between its contention that 50 Americans are being held in the U.S. compound in Tehran and the reports by the clergymen who visited the hostages that they saw only 43 captives.

Department spokesman Hodding Carter said the U.S. government stands by its contention that "50 Americans are held or should be held in the embassy compound." Whether some of the captives have been removed or were not seen by the clergymen for other reasons is a matter that only can be clarified by the Iranian authorities, since the United States has no way of verifying what the situation is inside the compound, he said.

Howard and his colleagues -- the Rev. William Sloane Coffin of New York's Riverside Church and Catholic Auxiliary Bishop Thomas Gumbleton of Detroit -- previously had refused to divulge what they saw during their five closely supervised hours in the embassy, presumably for fear of souring further contact with the student occupiers. In recounting tonight some of what they observed, the three continued to avoid description of exactly where the Americans are detained or any detailed account of living conditions inside the compound.

Foreign Minister Sadegh Ghotbzadeh, who received the three American churchmen this morning, pledged to seek an explanation for the confusion about how many hostages actually are in the occupied embassy. After five hours in the building, the ministers, who were accompanied by Cardinal Leon-Etienne Duval, archbishop of Algiers, concluded that they had seen only 43 Americans, despite the higher State Department estimate of 50.

A spokesman for the students told reporters today that the discrepancy of seven was because some hostages refused to attend the services. Another spokesman, also reached by telephone inside the embassy, had suggested yesterday that the missing hostages could have been refused permission to attend if they were suspected of espionage.

The student spokesmen frequently contradict one another and several groups within the embassy compound are said to be competing for authority and attention over the others, which often makes what they say inconclusive. Observers who have watched the students over the weeks raised the possibility of several plausible explanations for the confusion:

The students, split among themselves to some extent and inexperienced in any case, could have forced some of the most uncooperative hostages to stay away from the services as punishment, without realizing the extent of concern this would arouse.

The students also could have deliberately kept some hostages out of view in a calculated effort to keep the situation confused and generate as much uncertainty as possible in the United States.

Some hostages might have been transferred outside the embassy, as reported earlier but never confirmed by the students.

Coffin said the State Department also was contributing to the confusion by its refusal to reveal names of the hostages. He suggested the reluctance could be because some of them are Central Intelligence Agency employes with double identities.

"They know who is in there," he added. "They are afraid some guy has got two names, and they don't know which name he is using."

Coffin said the younger captives, especially the Marine guards, showed the greatest strain, and were having a difficult time adjusting to the inactivity.

"They're certainly not used to reading a lot of books," he said.

Coffin also said he met with Barry Rosen, the embassy's press attache, who was paraded outside the compound during the first week of the student occupation. When Rosen was told that his son, Alexander, had sent his father a gift, "His face lit up like a Christmas tree," according to the minister.

Earlier today, the clergymen visited the embassy charge d'affaires, L. Bruce Laingen, and two other American officials who have been held in the Foreign Ministry during the seven weeks of the embassy's occupation.

Laingen jogs up and down the ministry steps to keep fit, Coffin said, adding that all three men were being held in "high-level captivity."

Howard added that the three Americans in the Foreign Ministry "are under certain kinds of strain," especially Laingen who is obsessed with the plight of his compatriots in the embassy.

"Laingen is like the captain of the ship who is separated from his crew," Howard said in a television interview with ABC News.

Following the visit, the three ministers met with Ghotbzadeh. In the session the foreign minister gave "very little indication that there was any movement" toward resolving the hostage problem, Howard said. Coffin said he left the meeting thinking "both sides should try to understand each other . . . morally speaking, we're living in a glass house and people who live in glass houses shouldn't throw stones."

"If lives are to be saved," the New York minister added, "we must exercise restraint." Coffin recalled that during the visit on Christmas morning, one of the student captors complained to him that occupying the embassy was forcing him to neglect his studies in electronics.

"I offered him an easy solution," said Coffin.