While Kenya's politicians and press reacted sharply in public to the recent announcement that the United States would sell weapons to Somalia, which claims about a third of Kenya's territory, Kenyan Foreign Ministers Munyua Waiyake says privately that the announcement was no surprise and will not damage his country's excellent relations with the United States.

During recent years, American involvement in Kenya has expanded and relations have become so cordial that no other African country is now held in higher esteem by Washington.

This year the United States will give more development assistance to Kenya than to any other African country. The Kenyan foreign minister says, "We know we can depend on the United States."

Considered one of Africa's most stable and prosperous countries, Kenya was ruled by Britain until 1963, but recently American economic, political, cultural and now military interests have accelerated. About 5,000 Americans now live in Kenya, and another 50,000 visit as tourists each year.

A local editor remarked, "The United States is fighting against the Russians for influence all over Africa, but here in Kenya we are so pro-West that the only competition America has is Britain."

An articulate young Kenyan lawyer, relaxing in faded jeans and thumbing through back issues of Ms. magazine with Stevie Wonder blaring in the background, said, "I can't think of one person my age who has any love for the British, but we admire the Americans for their casualness and informality. American attitudes are now the trend in Kenya."

And the still-predominant British influence should not be belittled. One Kenyan Cabinet member is such an unabashed Anglophile that his countrymen refer to him simply as "the Englishmen."

The British still have a tremendous hold on Kenya's economy, but unlike most of their former African colonies, British interests in Kenya are not threatened by the prospect of nationalization. Here their challenge is growing American competition.

This competition is not just for a share of the growing Kenya market, but is also for subtle influence in the civil service, the educational system and even the mass media. More than a few British eyebrows were raised when Kenya's top journalist - Harvard trained - launched a highly successful weekly newsmagazine and, ignoring.The Times of London, took his foreign features from the New York Times.

"We're most comfortable with what we know and like to point others in that direction," said Okete Shiroya, dean of Kenyatta University College. Seventeen years ago he went to study in Minnesota as part of a massive airlift of Kenyan students to the United States, which seems now to be paying dividents to America.

Many of these American-oriented men have risen to influential posts in government, business and the professions. They are, to an immeasurable degree, responsible for Kenya's present pro-American course.

"Kenya is doing things the way we like to see them done," said an American diplomat recently. "It is friendly to the West and encourages free enterprise."

The United States stepped up its support for Kenya, an ideological ally, after getting its fingers burned in Angola. Last year then-Secretary of State Henry Kissinger visited Kenya three times, more than any other country on the continent.

An American military connection was negotiated after the Angolan war, and Kenya is buying, with American credit, a dozen supersonic Northrop F-5 fighter jets. Kenya has also expressed an interest in an American ground-to-air missile system.

The F-5 is designed to counter Russian MIG-21s, which are used by the air forces of Somalia and Uganda. Kenya almost went to war with Uganda last year and, just a few weeks ago, accused Somalia of attacking a remote Kenyan police post with thousands of soldiers.

Kenya's military ties to the United States were emphasized on independence day in December when the usual Kenya air force display was scrapped for a fleet of U.S. jets that flew over Nairobi's Jamhuri Park before President Kenyatta addressed the nation on Kenya's readiness to repel any attack.

One American diplomat said that display was "meant to show that Kenya has powerful friends."

In case anyone failed to get the message, in February, when Kenya's relations with Uganda plummeted, an American aircraft carrier, the U.S.S.-Enterprise, cruised into the Kenyan port of Mombasa with a big hoopla.

But military ties are developing slowly compared to America's economic interests in Kenya. Last year alone, thanks mainly to the surging price of coffee, Kenya's trade with the United States increased by almost 25 per cent, easily doubling the level of five years ago.

In fact, one of the first billboards one sees upon arrival here reflects the American business community's attitude: "General Motors Kenya Limited-With Full Confidence in the Economic Future of Kenya."

One hundred and ten American companies, with a total investment of $185 million, now do business in Kenya, almost all having moved in since independence. These include such giants as Firestone, Esso and IBM.

The only African countries boasting larger American investments are mineral rich Nigeria, Zaire and South Africa and Liberia.

Kenya's policy of allowing dividends to be reunited freely is no small inducement to the American business community, nor is the market potential of Kenya's fast growing middle class.

Many American firms such as Citibank and Union Carbide choose to locate their regional offices in Nairobi because communications and Western-style living here are the best in East Africa.

Ground has been broken for the construction of a new American embassy here in Nairobi, which will be one of Africa's largest. Already the Nairobi American embassy staff is bigger than in any African country except Nigeria. Nigeria has 80 million people and is now a chief supplier of oil to the United States, while Kenya has only 14 million people and provides no vital resources to the United States.

The United States Agency for International Development, which recently moved into Nairobi's newest skyscraper, employs 78 Americans, far more than in any other African country.

The United States will this year grant and lend Kenya $32 million in development assistance - 10 times the annual amount of the 1960s and discounting Food for Peace shipments, more than any other African country will receive.

Although once active throughout East Africa, the Peace Corps has terminated all of its programs in Kenya's neighboring countries, but Kenya has picked up the slack and expanded to 280 volunteers, one of the largest continengents in the world.

The country's stability and pro-Western outlook are generally attributed to the polices of the aging President Jomo Kenyatta. According to the consensus of informed diplomats and businessmen, there is no hint that any future Kenyan government might abandon capitalism or turn against the West.

"Though we'd like to see a more equitable distribution of social benefits," said one young Kenyan executive," too many of us have a stake in the present system to allow any radical changes.

"And," he added, "when we look at our neighboring countries where they talk a lot about socialism and revolution, we don't see much to emulate."