On the evening of January 2, six men were captured outside the fences of the US Marine base at Khe Sanh, in the Quang Tri province of Vietnam, apparently performing reconnaissance for a planned North Vietnamese attack.
A defector carried information about the attacks to the US forces on January 20, and the attacks themselves began the following day. The US and allied forces quickly joined battle, but were surrounded and besieged. For the next two months, the siege went on, until American forces broke through and relieved the base in March.
The American forces recorded a total of 730 soldiers killed in action, with a further 2,642 wounded and 7 more missing in action. Casualties on the North Vietnamese side are estimated as between 10,000 and 15,000.