Only one American who escaped from the besieged U.S. Embassy in Tehran Nov. 4 has retured to the United States so far: Kim King, a 27-year-old tourist caught up in what he recalls as a "nightmare."

"They started to come over the wall," King said as he recounted the embassy takeover by Iranian militants. "After about five minutes, we heard them on the roof. . . We were worried about getting ourselves out."

Even before the Nov.4 assualt, King noted, "I was ready to go home. Everything was mounting up. Naturally we (Americans) were a target." He said he was able to make his way back from Tehran because "I assured them that I was just an American tourist and I was very anxious to get home."

Six other Americans -- at least several of whom escaped with King during the embassy takeover -- left Iran last weekend after taking refuge at the Canadian Embassy in Tehran for nearly three months. None of these six has yet arrived back in the United States or publicly recounted the ordeal.

In interviews with The Washington Post, King, who left Iran Nov. 10 and who now lives in Portland, Ore., provided the first detailed account of a harrowing 3 1/2 hours spent barricaded in a dimely lit, second-floor consular section at the U.S. Embassy before the small group of Americans made their getaway.

A state Department official confirmed for the first time yesterday the overall accuracy of King's account, while saying he could not vouch for every detal. Previously, U.S. officals had been skittish about discussing King's statements, apparently because of fears of jeopardizing those Americans who took refuge at the Canadian Embassy.

In the telephone interviews, King recounted moments of fear when the Americans saw Iranians armed with machine guns and heard footsteps on the roof. "Then we started getting worried. We started looking for weapons," he said.

At one point, he added, and Iranian smashed a bathroom window and tried to force his way inside. But, King said, a Marine guard -- who he believes was Sgt. James Michael Lopez, 21 -- shoved the intruder back "out the window and fired tear gas at him."

There were also moments of wry humor as the Americans waited, uncertain what would befall them. "We had all been making kind of jokes about the situation," King said. "I suggested that we have a pizza and have it delivered."

Suddenly, the moment of escape arriveed. King and Mark J. Lijek, a consular official who later took refuge at the Canadian Embassy, were watching out two windows that looked down on a back alley. It was raining and the alley was largely deserted.

"When we saw there was no one outdoors" in the alley "we filed down the stairs," King recalled. A marine had jimmied the lock on a rear door. The captives quickly walked out. The Marine guards remained -- apparently out of a sense of duty to the embassy, King said.

The escape evidently was facilitated by the consular section's location -- on the perimeter of the embassy compound.

The identites of those who escaped with King are not clear. King said that six American officials fled with him, but he believes only four of them later took reuge in the Canadian Embassy. The whereabouts of the other two Americans -- if King's recollection is correct -- remains uncertain.

In addition to the Americans, King said, about 15 to 20 Iranians escaped with him from the U.S. Embassy. Some were embassy employes, he said, while other were at the consular section seeking U.S. visas.

After their escape, the Americans and their Iranian colleagues walked about four blocks from the besieged embassy, King said. Then the Iranians broke away, apparently heading for their homes. King said the six Americans with him said they would go to the British Embassy. He decided to go to the Iranian customs office in an attempt to get an exit visa.

Since then, King said, he had been uncertain about what became of the other Americans and concerned about their welfare. An Iranian previously employed by the U.S. Embassy assured him that the six Americans were "all right." King said he assumed they were hiding at friends' homes in Tehran.

Earlier this month, King accused the State Department of abandoning the six Americans to an uncertain fate. "They're trying to hide something," he charged. When he learned yesterday that six Americans had been freed after taking refuge in the Canadian Embassy, King said, "That's great. It really is."

King's departure from Iran according to the account he provided, was marked by further drama, including a threatened appearance before an Iranian court and a $500 payment by an Iranian acquaintance to help him obtain exit documents.

King arrived in Tehran last year at the end of what he described as a long trip through parts of Europe, eventually reaching Yugloslavia and Turkey. His passport has been stolen, he said. He was running out of money and he added, "I had overstayed my visa."

He had gone to the U.S. Embassy in Tehran to read a Telex message from his parents in Oregon. He had asked them for money to help pay his air fare home and they wired back, "We're going to try to help." Shortly after he picked up the Telex, the embassy came under attack.

During his 3 1/2 hours in the besieged compound, King said, the electric power was cut, leaving part of the consular section in "pitch-black" darkness. Most of the windows were boarded up, he said, because of previous violence. King said he helped fasten the doors using wire hangers.

At the Iranian customs office, he said, he was given "a real hassle" because his new passport, the replacement for the one that was stolen, did not show the date he entered Iran. Within several days, he said, an entry date was obtained, but he faced new problems because of his expired visa.

King was ordered to appear in court to review his visa status but, he said, "I didn't want to go to court because most of what the courts were doing -- they were just shooting people." Instead, he went to see Iranian police officials to persuade them to let him go home. He did not let them know he had been inside the besieged embssy, he said.

The police summoned an Iranian formerly employed by the U.S. Embassy, a man whose name King declined to disclose. "I told him what my situation was," King said. The Iranian agreed to pay a $500 fine levied against King because of his expired visa. The payment cleared King's way to go home.

By then, his parents had arranged to provide most of his airfare and on Nov. 10, King said, he departed on a British Airways fight to London.