TOKYO, AUG. 7 -- Former prime minister Nobusuke Kishi, 90, who sought to strengthen ties with the United States through a controversial revision of the 1951 U.S.-Japan Mutual Security Treaty, died of a heart ailment today at a Tokyo hospital.

Two months after the treaty revision was ratified, Mr. Kishi, who served as premier from 1957 to 1960, was forced to resign after popular protests by opponents who saw the pact as solidifying an alliance that could draw Japan into a nuclear war.

During World War II, Mr. Kishi had been a top government official in the Japanese war effort against the United States. In 1941, he joined the Cabinet of Gen. Hideki Tojo as minister of commerce and industry. He was one of the signers of Japan's declaration of war.

He served as wartime vice minister for military procurement and as minister without portfolio with responsibility for war mobilization. He reportedly became increasingly opposed to Tojo's insistence on continuing the war despite Japan's heavy losses, and he may have contributed to the collapse of Tojo's government in 1944.

After Japan's surrender, Mr. Kishi was imprisoned as a war criminal for 3 1/2 years without trial, as were many officials in high posts. Upon release, he returned to politics and was elected to the lower house of the Diet, Japan's parliament, in 1953.

In 1955, he was a main architect of the merger of two conservative parties into the Liberal Democratic Party, which has controlled Japan's government since.

Mr. Kishi was appointed deputy prime minister and foreign minister by Prime Minister Tanzan Ishibashi in December 1956, and assumed the premiership in February 1957, when Ishibashi resigned because of ill health.

One of Japan's worst postwar political crises erupted after Mr. Kishi sought to strengthen ties with the United States by revising the treaty signed in 1951 at the end of U.S. occupation.

Although the revisions banned U.S. forces from interfering in domestic riots in Japan and allowed abrogation of the treaty by either side rather than requiring mutual agreement, many groups opposed renewing the 1951 treaty at all, or thought the revisions still favored Washington too much. Leftists and many moderates feared an alliance with the United States could drag Japan into nuclear war.

Mr. Kishi wanted the new treaty ratified before a scheduled visit to Japan by President Dwight Eisenhower in June 1960. As a parliamentary deadline neared, members of the opposition Socialist Party blocked the house speaker from the podium and were dragged from the chamber by police.

Mr. Kishi's backers forced the measure through a midnight session attended only by members of the governing Liberal Democrats. The action triggered demonstrations by hundreds of thousands and work stoppages by millions. More than 13 million people signed petitions demanding new elections.

Although there was little violence, Mr. Kishi's government was forced to cancel Eisenhower's visit because it could not guarantee his safety.

After the treaty took effect June 23, Mr. Kishi resigned as prime minister. The protests then subsided relatively quickly.

Mr. Kishi continued to serve as a member of the Diet until 1979. His daughter, Yoko, is married to Shintaro Abe, a former foreign minister who is chairman of the Liberal Democrats' Executive Council and a leading contender to succeed Prime Minister Yasuhiro Nakasone this fall.

Mr. Kishi's younger brother, Eisaku Sato, served as premier from 1964 to 1972. Mr. Kishi was adopted at age 15 into the family of his uncle, who had no sons, and changed his name.