LONDON (AP) _ Robert B. Tuckman, who covered the Vietnam and Korean wars in a career with The Associated Press that spanned four decades, has died. He was 85.

Tuckman was diagnosed with a brain tumor and liver cancer several weeks ago. He died in London on Sunday night, his family said.

He directed coverage of the Tet offensive that shattered official U.S. claims that the Vietnam war was being won. When Tet brought the fighting to Saigon's streets in January 1968, Tuckman ran the bureau virtually around the clock, even running errands such as picking up military rations for the staff.

``Tuck,'' as he was known, spent 2 1/2 years in Vietnam, and was the AP's chief correspondent there in 1967-68, applying skills he had learned as the AP's field director in Korea from 1951-53.

Tall, bald and with a friendly manner, Tuckman laced his speech with erudite humor and quaint expressions, such as calling reports of fighting ``advices from the field.''

He also was a consummate news agency journalist _ fast, thorough and resourceful.

Longtime friend George McArthur, also a war correspondent in Korea and Vietnam, recalled how Tuckman solved a problem faced by every wire service reporter _ what to put in the second paragraph after the ``bulletin'' lead covered everything immediately known on a major breaking story.

``If the bulletin was all about shot and shell, Tuck would put in a second graf saying something like, `Senior officers at 8th army headquarters made no attempt to disguise their dismay','' McArthur said.

Tuckman was born March 5, 1913, in New York. He earned a journalism degree at New York University and worked on newspapers in Saranac Lake, N.Y., and Rutland, Vt., before joining the AP in 1940.

He worked in Albany and Syracuse before taking military leave in 1942 to serve as a Marine captain in the Pacific during World War II.

Rejoining the AP in 1945, Tuckman spent the next two decades reporting from Albany N.Y., Los Angeles, Tokyo, Seoul, South Korea and Berlin; later as bureau chief in Nicosia for Cyprus and Israel and in Honolulu; and in Hong Kong and London, as news editor, before he moved to Saigon.

He retired to the Seychelles Islands in 1969, but soon tired of the slow pace of life and returned to London.

He came out of retirement from time to time during the 1970s to serve as acting London news editor when vacancies occurred.

Tuckman is survived by his wife, Ann, who said he will cremated privately.