Hostage journalist Charles Glass, whose captors yesterday released a video tape in which he says he is a U.S. spy, has never worked for the Central Intelligence Agency or any other branch of the U.S. government, White House and State Department officials said.

U.S. officials said publicly and privately that they believed the video tape of former ABC News correspondent Glass was the result of coercion, with his kidnapers using death threats or torture to make him read the statement for the camera.

Friends of Glass and other journalists said the video tape shows that he was not speaking normally and was obviously reading language he had not written.

No one contacted expressed a belief that Glass had ever worked for an intelligence organization or that he was on a spy mission while researching a book in Beirut, where he was captured June 17.

"That's obvious nonsense," said Ed Turner, executive vice president of Cable News Network. "He's too good a journalist to ever get involved in anything like that, and I would have thought the bad guys over there were more sophisticated than that by now."

A poignant moment for U.S. television viewers occurred unexpectedly shortly after noon yesterday when ABC News anchor Peter Jennings interrupted coverage of the Iran-contra hearings to show the video tape of his close friend and former ABC colleague.

After the tape had aired, Jennings fought back tears and seemed to struggle for words. He switched quickly to ABC's State Department correspondent for a live report. When Jennings returned to the screen he apologized for his "hesitation," explaining that like most American viewers, he had just seen the tape for the first time.

As he began to read a statement from ABC News President Roone Arledge, Jennings regained his composure and said of Glass, "All of his friends who know him know that he doesn't even talk like that."

Other associates of Glass who had seen the tape noted that his accent seemed strained, the grammar was foreign and the sound of pages being turned made it obvious he was reading from a statement prepared by someone else.

For example, Glass, who had returned to Beirut to gather information for a book on the Middle East, read that he returned "to get the last {not latest} information in this area . . . . "

"It certainly does not sound like him. I didn't think he looked as depressed as the {wire service} copy said, but it was a completely artificial performance," said David Blundy, a Washington correspondent for the London Sunday Telegraph who knows Glass from their years covering the Middle East together.

"Of course he's not {a CIA agent}," said Fred Barnes of The New Republic magazine. Barnes, an organizer of a group of journalists circulating petitions on behalf of Glass and another hostage journalist, Terry Anderson of the Associated Press, added: "Look at his reporting. It certainly doesn't follow American policy because if anything, he's pro-Arab and tilted away from Israel. There is simply no reason to believe Charlie Glass is a CIA agent."

Asked whether Glass was "an agent, either directly or indirectly, for the CIA or any other U.S. intelligence agency," White House spokesman Marlin Fitzwater said, "No, he was not." Asked if that was a categorical denial, Fitzwater said, "Yes."

A senior White House official said the charge that Glass is a spy was "made up of whole cloth," adding, "This is just {the pro-Iranian Shiite Moslem group} Hezbollah's excuse for not releasing Glass."

State Department spokesman Charles E. Redman said Glass "is not now and never has been an employe of the United States government."

In recent weeks, journalists' groups have begun lobbying privately for the release of Glass and Anderson, the AP Beirut bureau chief taken captive in March 1985.

Barbara Koeppel, executive director of the Committee to Protect Journalists, said a group of U.S. journalists visited the Syrian charge d'affaires in Washington July 1 to "try to see if there was anything we could do." Among those at the embassy were Jennings, ABC Washington bureau chief George Watson and Mary McGrory, columnist for The Washington Post.

"I can't begin to make an assumption under which {Glass} said what he did," Koeppel said, "unless it was that he figured all of those who knew him would believe it was a preposterous statement."