Two Vietcong operatives detonated a car bomb underneath the hotel, which housed United States Army officers.

Following World War II, the communist-dominated Viet Minh fought the French colonial forces in an attempt to gain Vietnamese independence.

After the French defeat at the Battle of Dien Bien Phu in 1954, Vietnam was partitioned at the 17th parallel, pending national reunification elections in 1956.

In the late 1950s, South Vietnamese guerrillas known as the Vietcong—covertly supported by North Vietnam—began an insurgency with the aim of forcefully reunifying the country under communist rule.

[1] The building housed United States Army officers, including lieutenant colonels and majors,[9] and attracted off-duty personnel with its highly regarded food and drink, rooftop seating areas and movie screenings.

The buffer zone was used as a carpark and the streets adjoining the hotel were heavily lit and guarded by Vietnamese personnel at all times.

Noting that South Vietnamese officers mingled freely with Americans, they obtained ARVN uniforms from Saigon's black market, enabling them to get closer.

He recalled that the number of American officers at the Brinks Hotel had swelled on Christmas Eve because they were using the building to coordinate their celebrations, and that the attack would therefore cause more casualties than on a normal day.

[13] The bombers planted explosives weighing approximately 90 kilograms (200 lb)[12] in the trunk of one of the cars, and set a timing device to trigger the bomb at 17:45, during the happy hour in the officers' bar at the hotel.

[1][2][12] The first and highest-ranking officer killed was Lieutenant Colonel James Robert Hagen, who had served in the army for 20 years and was working for MACV.

[8] Flying debris damaged nearby buildings, including the living quarters for enlisted men located across the street, and Saigon's two leading hotels, the Caravelle and the Continental.

The force of the explosion also shattered windows at the United States Information Service two blocks away and in shopfronts on the main shopping promenade Rue Catinat.

[8] The blast destroyed the studios of the Armed Forces Radio Service, which were on the ground floor of the hotel, but the station returned to the airwaves two hours later, using an emergency transmitter.

[8] The explosion forced the US to fly in more bomb-detection equipment, as most of the devices already in Vietnam were stored inside the hotel and were destroyed in the attack.

[15] The attack surprised American officials and policymakers on Vietnam, who were confident that the South Vietnamese government was in control in Saigon and that the Vietcong were only a threat in rural areas.

[17] The infighting exasperated Maxwell Taylor, the US ambassador to South Vietnam and former chairman of the US Joint Chiefs of Staff,[2] who felt that the disputes between the junta's senior officers were derailing the war effort.

[20][21] Khanh explicitly denounced Taylor in an interview published in the New York Herald Tribune on 23 December,[19][21] and on the day of the bombing, he issued a declaration of independence from "foreign manipulation".

Taylor messaged Washington on Christmas Day,[2][22] saying, "Hanoi will get the word that, despite our present tribulations, there is still bite in the tiger they call paper, and the U.S. stock in this part of the world will take sharp rise.

"[17] At the time, Johnson was reluctant to accede to his officials' calls for large-scale bombing of North Vietnam, a strategy that eventually became policy.

David Tucker of the United States Army War College said that the bombing was "insignificant for the conventional military balance but important for the political struggle that was the primary focus of the enemy [Vietcong]".

[28] The facility was repaired and American officers continued to stay there until the fall of Saigon on 30 April 1975, when the communists overran South Vietnam and reunified the country under their rule.