Graham Greene, whose widely acclaimed novels of international political intrigue and moral dilemma captivated readers for a half-century, died this morning in Switzerland. He was 86.

The author died at La Providence Hospital in the town of Vevey, near Lake Geneva, where he had been hospitalized for several days. Hospital director Robert Bertschy said the cause of his death was not immediately known.Greene combined a passion for politics, exoticism and religion in his long career.

"Graham Greene's place is secure as one of the greatest British novelists of the 20th century," said Tony Lacey, publishing director of Penguin Books in Britain.

Greene, who had a home in Antibes on the French Riviera, is the author of such celebrated novels as "The Power and the Glory," "The Third Man" and "The Quiet American."

He turned many of his stories into successful movie scripts, including "Our Man in Havana" and "The Comedians."

Greene traveled widely and many of his most successful novels had a political thrust.

Critics said his novels sought to convey a sense of morality and hope to man, whom he saw as plagued by frustration and despair. But Greene, a Roman Catholic convert, viewed many of his novels as "mere entertainments."

Yet it was his unique craftsmanship in creating atmosphere and characters that won his widest acclaim.

Greene's works combined elements of the spy thriller and the psychological drama whose heroes acknowledge their sins and thus achieve salvation.

For millions of readers his name was synonymous with action, intrigue, suspense and mystery, but Greene did not think he had talent, just patience and a penchant for hard work.

Greene would spend months on location, painstakingly gathering material for a novel, but his life lacked the colorful adventures of his characters.

"I have spent almost as much time with imaginary characters as with real men and women," he wrote in his autobiography published in 1971. Nor could he remember anecdotes about his real friends. "The only stories which I faintly remember are the stories I have written," he said.

The stories were compelling parables of the damned, born, he said, "out of my own sense of failure and boredom."