USS Nimitz heads west from South China Sea amid Middle East tensions

One of the sources said the US Embassy in Hanoi had informed him about the cancellation, due to, "an emergent operational requirement."

The embassy didn't immediately respond to a Reuters request for comment.

The Nimitz carrier strike group conducted maritime security operations in the South China Sea last week, as, "part of the US Navy's routine presence in the Indo-Pacific," according to the website of the Commander of the US Pacific Fleet.