U.S. tracking high-altitude balloon first spotted off Hawaii coast

The U.S. military is tracking a high-altitude balloon that was observed off the coast of Hawaii over the weekend, officials said Monday. The balloon's owner is unknown, but there were no indications it was maneuvering or being controlled by a foreign actor.

The balloon was detected and observed floating at approximately 36,000 feet above the Pacific on April 28. It did not directly pass over sensitive sites or defense critical infrastructure, according to U.S. officials. 

One official said the object did not pose a military or physical threat to people on the ground, nor did it pose a risk to civil aviation over Hawaii despite its altitude. NBC News first reported its detection earlier Monday.