• The Pentagon is tracking a high-altitude balloon spotted in Hawaiian airspace.
• The device, floating at 36,000 feet, is not a threat to civilians, the Department of Defense said.
• Three Chinese surveillance balloons were shot down across the US earlier this year.

Another mysterious balloon has been spotted over US airspace.

A high-altitude balloon, spotted floating at 36,000 feet, is being tracked by the Department of Defense after being spotted over Hawaii on April 28.

"The balloon did not transit directly over defense critical infrastructure or other U.S. Government sensitive sites, nor did it pose a military or physical threat to people on the ground," A Department of Defense spokesperson told Insider in an emailed statement. "Although it was flying at an altitude used by civil aviation, it posed no threat to civil aviation over Hawaii."

Based on these observations, officials determined no military action need be taken against the balloon, which had floated out of Hawaii's airspace and territorial waters.

"Ownership of the balloon is unknown, but there is no indication that it was maneuvering or being controlled by a foreign or adversarial actor," the Department of Defense statement continued.

The balloon, which will continue being tracked by the DOD and Federal Aviation Administration, is the latest known device spotted floating over the United States. In February, three objects — later determined to be Chinese spy balloons — were shot down across the country.