June 9 (UPI) -- Two U.S. Air Force bombers flew over the disputed South China Sea during a 10-hour exercise, the U.S. Pacific Air Forces announced.
In the joint exercise Thursday between the Air Force and the Navy, the B-1B bombers flew from Guam in conjunction with the USS Starett, a guided missile destroyer.
A statement:by the PACAF, the air component of the U.S. Pacific Command, made no mention of China's territorial claim to most of the South China Sea, nor did it suggest the exercise was a challenge to China's perceived sovereignty over the area. Seven nations border the sea.
B-1B bombers were also recently sent to the Korean peninsula for joint exercises with South Korean and Japanese troops, as a warning to North Korea.
The Chinese Defense Ministry said Friday it was monitoring Thursday's U.S. military exercises. In a statement Friday, it said that "China always remains vigilant and keeps effective surveillance over the military activities of the related countries in the South China Sea."
The statement specifically mentioned the presence of "B-1B's flying over the South China Sea on June 8."
In an annual report released this week, the Pentagon noted that China was contracting 24 hangars, fixed-weapons positions and other military infrastructure improvements on the Spratly Islands, South China Sea islands it occupied in 2016.