A Boeing jet set to be delivered to Xiamen Airlines in China was returned to the U.S. amid a growing trade war between the two nations.

A second Boeing ( NYSE: BA) 737 MAX jet, originally designated for delivery to a Chinese airline, was en route back to the United States on Monday, Reuters reported, citing flight tracking data. The plane's return may be another sign of rising trade tensions between Washington and Beijing.

Boeing has begun recalling a few 737 MAX aircraft that were initially ordered by Chinese carriers amid trade rift.