Malcolm W. Browne, whose reporting during the early stages of the Vietnam War won a Pulitzer Prize and whose photograph of a Buddhist monk setting himself on fire became an indelible image of the in­trac­table conflict, died Aug. 27 at a hospital in Hanover, N.H. He was 81 and lived in Thetford Center, Vt.

His wife, Le Lieu Browne, confirmed his death to the Associated Press. He had Parkinson’s disease.

Mr. Browne went to Vietnam in 1961 as the Saigon bureau chief of the Associated Press and was one of the first reporters to cover the growing conflict that would ultimately claim more than 50,000 U.S. lives.

He chronicled the regime of South Vietnamese President Ngo Dinh Diem and the homegrown opposition led by Buddhist monks. On June 11, 1963, Mr. Browne was present when an elderly monk named Thich Quang Duc, wearing sandals and a robe, calmly sat cross-legged on a cushion in the center of an intersection in Saigon.

Other monks poured fuel over him, and the monk struck a match and was immediately engulfed in flames. Mr. Browne shot roll after roll of film, documenting the self-immolation.

AP Saigon correspondent Malcolm Browne goes on patrol near Binh Hia, South Vietnam with South Vietnamese troops in 1965. (AP)

“Everybody that witnessed this was horrified,” Mr. Browne said in a 2011 interview with Time International. “It was every bit as bad as I could have expected. The main sound was the wailing and misery of the monks, who had known this guy for many years before and were feeling for him.”

Afterward, he sent the film with a passenger on a commercial flight to Manila. When the AP made the graphic images public, the sense of shock was felt around the world.

“The picture he took was the equivalent of going viral today,” William Prochnau, author of “Once Upon a Distant War: Young War Correspondents and the Early Vietnam Battles,” said Tuesday. “As soon as he got it out of there, it was in every paper in the world.”

Mr. Browne’s photograph drew unprecedented attention to U.S. involvement in Vietnam. Within months, the administration of President John F. Kennedy abandoned support for the Diem regime, which collapsed Nov. 1, 1963, when Diem and his brother, Vietnamese security chief Ngo Dinh Nhu, were overthrown and killed in a U.S.-supported coup.

In the meantime, Mr. Browne continued reporting on the escalation of U.S. military operations in Vietnam, sometimes smuggling his stories out through couriers. When he tried to photograph U.S. pilots flying combat missions, in violation of their official non-combat roles, his camera was seized.

A Navy admiral, annoyed by Mr. Browne’s persistent questioning, once asked him, “Why don’t you get on the team?”

In 1964, Mr. Browne shared the Pulitzer Prize for international reporting with David Halberstam of the New York Times.

His photograph won international awards but not the Pulitzer, which was awarded to Robert Jackson of the Dallas Times Herald for his image of Jack Ruby fatally shooting Lee Harvey Oswald. Nonetheless, Mr. Browne’s photo remains one of the most powerful images of a war that continues to reverberate in the national memory.

“His magic moment was the picture,” Prochnau said of Mr. Browne. “I think, without any doubt, it laid the groundwork for a lot of the opposition that came afterward. It told the administration that they just couldn’t win under Diem, that he didn’t have control of his country.”

Malcolm Wilde Browne was born April 17, 1931, in New York City. His father was an architect, and a grandfather was a first cousin of 19th-century writer and wit Oscar Wilde.

Mr. Browne studied chemistry at Swarthmore College in Pennsylvania and worked as a chemist in the 1950s.

He was drafted into the Army in 1956 and ended up by chance working at the military newspaper Stars and Stripes in Korea. After newspaper and wire-service jobs, Mr. Browne went to Vietnam, where he, Halberstam, the AP’s Peter Arnett and Neil Sheehan of United Press International were part of a young press corps.

Mr. Browne was known for wearing red socks and listening to opera in his Saigon apartment. He wore a solid-gold bracelet for use as barter or bribery, in case he was captured.

He once confronted Vietnamese agents with a submachine gun when they tried to arrest his Vietnamese-born wife on trumped-up charges. As a grisly memento of the war raging in the countryside, he kept a dismembered hand on his office wall in Saigon.

In 1965, Mr. Browne joined ABC News and then wrote for magazines before joining the New York Times in 1968. He covered South America, Eastern Europe and Asia for the Times and returned to Vietnam in the early 1970s.

He was one of the last correspondents out of Saigon when the city fell to North Vietnamese forces in April 1975.

“Friends remember him that last day,” Prochnau wrote in his book, “sitting on a battered combat helmet, head in hands, weeping, waiting for the last helicopters to lift away from a wrecked country and a wrecked dream.”

His first marriage, to Diana Kirchwey, ended in divorce. Survivors include his wife of 46 years, Le Lieu Browne; a daughter from his first marriage; a son from a second marriage; a brother; a sister; and two grandchildren.

In the early 1980s, Mr. Browne was an editor at Discover magazine before returning to the Times in 1985 as a science writer.

At 61, he was the oldest accredited correspondent covering the Persian Gulf War. He retired in 2000.

In 1993, Mr. Browne published a memoir, “Muddy Boots and Red Socks,” about his experiences as a foreign correspondent.

“In Viet Nam,” he wrote, “it was said that there were two kinds of observers: those who heard about the war from others and those with muddy boots. I preferred the latter category.”