Operation Formation Star placed a considerable strain on the United States Seventh Fleet's support for the Vietnam War, particularly aircraft carrier operations with Task Force 77 at Yankee Station in the Gulf of Tonkin ("picture"). Two days before the capture of the "Pueblo", 21 January 1968, North Vietnamese Army began its siege against Khe Sanh Combat Base near the Vietnamese Demilitarized Zone (DMZ). Seven days after the "Pueblo" crisis started, the Viet Cong and North Vietnamese People's Army of Vietnam launched the Tet Offensive, a campaign of surprise attacks against military and civilian commands and control centers throughout South Vietnam. Concurrent with both events, Task Force 77's support of Operation Rolling Thunder was greatly hampered by poor weather conditions over North Vietnam.