The was no word of the death in state-controlled media late Friday, but the news had spread widely in Facebook and other social media.
Giap was a national hero whose legacy was second only to that of his mentor, founding President Ho Chi Minh, who led the country to independence.
The so-called "red Napoleon" stood out as the leader of a ragtag army of guerrillas who wore sandals made of car tires and lugged their artillery piece by piece over mountains to encircle and crush the French army at Dien Bien Phu in 1954. The unlikely victory, which is still studied at military schools, led not only to Vietnam's independence but hastened the collapse of colonialism across Indochina and beyond.
Giap went on to defeat the U.S.-backed South Vietnam government in April 1975, reuniting a country that had been split into communist and noncommunist states. He regularly accepted heavy combat losses to achieve his goals.
"No other wars for national liberation were as fierce or caused as many losses as this war," Giap told The Associated Press in 2005 in one of his last known interviews with foreign media on the eve of the 30th anniversary of the fall of Saigon, the former South Vietnamese capital.
"But we still fought because for Vietnam, nothing is more precious than independence and freedom," he said, repeating a famous quote by Ho Chi Minh.
Giap remained sharp and well-versed in politics and current events until he was hospitalized. Well into his 90s, he entertained world leaders, who posed for photographs and received autographed copies of his books while visiting the general's shady colonial-style home in Hanoi.
Although he was widely revered in Vietnam, Giap was the nemesis of millions of South Vietnamese who fought alongside U.S. troops and fled their homeland after the war, including the many staunchly anti-communist refugees who settled in the United States.
Born Aug. 25, 1911, in central Vietnam's Quang Binh province, Giap became active in politics in the 1920s and worked as a journalist before joining the Indochinese Communist Party. He was jailed briefly in 1930 for leading anti-French protests and later earned a law degree from Hanoi University.
He fled French police in 1940 and met Ho Chi Minh in southwestern China before returning to rural northern Vietnam to recruit guerrillas for the Viet Minh, a forerunner to the southern insurgency later known as the Viet Cong.
During his time abroad, his wife was arrested by the French and died in prison. He later remarried and had five children.
In 1944, Ho Chi Minh called on Giap to organize and lead guerrilla forces against Japanese invaders during World War II. After Japan surrendered to Allied forces the following year, the Viet Minh continued their fight for independence from France.
Giap was known for his fiery temper and as a merciless strategist, but also for being a bit of a dandy: Old photos show him reviewing his troops in a white suit and snappy tie, in sharp contrast to Ho Chi Minh, clad in shorts and sandals.
Giap never received any formal military training, joking that he attended the military academy "of the bush."
At Dien Bien Phu, his Viet Minh army surprised elite French forces by surrounding them. Digging miles (kilometers) of trenches, the Vietnamese dragged heavy artillery over steep mountains and slowly closed in during the bloody, 56-day battle that ended with French surrender on May 7, 1954.
"If a nation is determined to stand up, it is very strong," Giap told foreign journalists in 2004 prior to the battle's 50th anniversary. "We are very proud that Vietnam was the first colony that could stand up and gain independence on its own."