NAIROBI, KENYA, NOV. 17 -- It is the most extraordinary of African coup plots.

As it has unfolded in the past five days on the front pages of the government-controlled newspapers here, seven American missionaries allegedly schemed with the Ku Klux Klan to overthrow the government of Kenyan President Daniel arap Moi.

But, as the newspapers here have explained it, the Kenyan government discovered and aborted the purported plot. And last Friday, the missionaries and their families were summarily thrown out of the country.

There are "non-Kenyans among us who have come to our country for carefully disguised purposes," declared Moi in a speech. "No government can sit idle in the face of attempts at sabotage and destabilization."

Picking up on the warning of their president, scores of high-ranking politicians here have warned the wananchi, or common people of Kenya, to be on the lookout for "evil foreigners" who pretend to do the Lord's work.

Security officials have searched a number of American houses in the past two days and picked up a Kenyan clergyman. Today, they seized the passports of three American missionary families and threatened them with expulsion.

What makes the rumored coup, the outpouring of fiery rhetoric and the police action so extraordinary is that, according to the U.S. government, the plot is a hoax.

The U.S. Embassy in Nairobi issued a statement today saying the only known evidence of the plot -- a purported Ku Klux Klan fund-raising letter written on the stationary of a small rural church in North Carolina -- is a "forgery."

The embassy statement said the expelled missionaries and the North Carolina church "appear to have been the victims of a hoax or fraudulent scheme which the American authorities are still investigating. The American government is seeking the support of the government of Kenya in explaining the facts to the public."

The affair of the KKK plot that wasn't appears to have strained relations between the U.S. government and this East African country, which for decades has prided itself on its special and friendly relationship with the United States.

An estimated 20,000 Americans live in Kenya, about 7,000 of whom are missionaries. Kenya has long been one of the largest recipients in sub-Saharan Africa of U.S. economic and military aid -- about $53 million this year. Under a 1980 defense treaty, the U.S. military has access to Kenyan airports and ports on the Indian Ocean.

A senior American diplomat here said the U.S. government is "puzzled" over why a friendly government would give credence to the "ludicrous" plot.

According to sources here, the Kenyan government ordered local newspapers to give it banner-headline coverage.

The American diplomat said the embassy is worried that American citizens may be harassed or injured as a result of high-level statements that could encourage anti-American violence in rural areas, where most of the missionaries live and work.

According to interviews here and in the United States with missionaries and U.S. officials, the unprecedented expulsion of American missionaries last week has nothing to do with the KKK, the American white supremacist organization.

Rather, according to these sources, the forged letter that led to the expulsions was the trump card in a bitter, internecine dispute between the now expelled American missionaries and a Kenyan-born preacher named David M.S. Kimweli, who lives in Carrollton, Ga.

U.S. officials say American immigration officials are now looking for Kimweli, who, according to missionary and diplomatic sources, has traveled across the South in recent years raising money for missionary efforts that he claimed to have organized in Kenya.

Letterheads bearing Kimweli's name say he is president of at least two Kenyan-based churches -- Reach and Touch Global Ministries and the Kenya Christian Evangelistic Outreach Mission. Neither of these, however, is registered as a church with the Kenyan government.

Kimweli, 32, went to the United States in 1983 to attend Johnson Bible College in Knoxville, Tenn., according to the school's president, David Eubanks.

Stevan McClure, pastor of Smoky Mountain Christian Church in Sevierville, Tenn., said Kimweli was ordained on June 8, 1986, as a minister in his church.

"The church without good reason ordained him before anyone checked anything out. . . . Scriptures say not to lay hands on someone hastily," McClure said. He added that Kimweli, since his ordination, has been involved in "conduct unbecoming that of a minister. . . . We are in the process of defrocking him."

Kimweli makes a strong and persuasive impression, according to the Rev. Kenneth A. Caswell, pastor of Foscoe Christian Church in Boone, N.C. Caswell said today that Kimweli spoke several times at his church last February.

"He brought exciting and stirring news. . . . Things he had seen, some rather miraculous occurrences -- sight being returned to the blind, objects speaking. He had very good command of the English language," Caswell said.

It was Kimweli's eloquent fund-raising appearances at a number of churches in the South that attracted to Kenya the seven American missionaries who were expelled from this country last week.

"All the people mentioned in the Ku Klux Klan letter were attracted by Kimweli to work in Kenya," said Jerry Sauder, an American Mennonite missionary who works in the Kenyan town of Thika.

According to Sauder, who worked closely with one of the expelled missionary families, Paul and Marty Hamilton and their three children, the seven missionaries all came to Kenya expecting to work for Kimweli's churches.

But Sauder said that when they arrived in Kenya, they found that the churches did not exist and that Kimweli had made false promises about their living arrangements. The missionaries had to scramble to find other churches to work for, said Sauders, whose church took in the Hamilton family.

Paul Hamilton, a television engineer who moved his family from Seymour, Tenn., to Thika in July, was apparently enraged by Kimweli's false promises.

Hamilton reported Kimweli's fund-raising activities to the U.S. Embassy in Nairobi two weeks ago, U.S. officials say. Hamilton also wrote a number of letters to churches in Tennessee, warning them about the Kenyan preacher.

"I don't believe {Kimweli} ever dreamed that we would sell our house, cars and come lock, stock and barrel to Kenya," Hamilton wrote in a letter in September to Rev. McClure at Smoky Mountain Christian Church. "When he did see that we had determined to come, he got scared and would not answer our telephone calls."

Hamilton also wrote: "Now the real problem is that {Kimweli} is applying pressure in Kenya to shut up the people over here."

The apparently forged letter that ran here on the front pages of Kenya's three daily newspapers last Saturday appears to have been part of the pressure that Kimweli applied against the disgruntled American missionaries, according to missionary and diplomatic sources.

The letter, which federal investigators say was forged on stationery purloined from Foscoe Christian Church in Boone, N.C., is addressed: "To Klu {sic} Klux Klan members."

"I am writing this letter to you all to remind you of the obligation of raising the funds that we need. So far we have raised {$80 million}. We are in need of {$20 million} urgently. As you already know, these funds are to topple those governments surrounding South Africa. Our strategy has been to begin with Kenya . . . .

"Paul and Marty Hamilton stationed in Thika, only about 20 miles from Nairobi, {are} among natives who are dissatisfied with the present governments. {They have} had great success. They used the funds to bribe the government officials and also to equip them with automobiles, computers and telephones."

The letter goes on to detail the alleged subversive activities of the other American missionaries who were deported last Friday. Hamilton, contacted by phone today in his hometown in Tennessee, said he had no idea until he returned to the United States this past weekend why he was deported from Kenya.

American diplomats here say they cannot understand why a supposedly friendly government would fail to seek any explanation from U.S. officials before it publicized the alleged plot or why the government here chose not to give the U.S. Embassy any prior notification of the expulsions.

The Kenyan government, thus far, has not backed down publicly from its insistence that the KKK plot was authentic. While the government has not yet made any official retraction, sources here said today that Moi privately has ordered senior party officials to stop making public statements about the Ku Klux Klan. Moi reportedly said the government is conducting its own investigation.

Last year, Moi accused some American missionaries of importing weapons to try to destabilize Kenya. Further investigation found that the missionaires had brought in air rifles to kill predators in rural areas. All charges against the missionaries were dropped.

Staff writer Mary Battiata in Washington contributed to this report.