The U.S. Federal Aviation Administration(FAA) reportedly issued an alert to U.S. commercial airliners earlier this month, warning of possible missile launches by North Korea.

According to ABC News on Monday, the U.S. FAA issued the alert warning of "longer-range missile test launches prior to the end of 2019, or in the early part of 2020." 

The report said that North Korea's warning that it will deliver a "Christmas gift" to the U.S. has put American and South Korean officials on high alert this week for a potential long-range missile test.

In a statement earlier this month, North Korea's vice minister of foreign affairs said that what is left to be done now is "the U.S. option" and it is entirely up to the U.S. what Christmas gift it will select to receive. Pyongyang has been urging the U.S. to show more flexibility in denuclearization talks by a self-imposed year-end deadline.