North Korea transmitted mysterious coded messages on Thanksgiving morning (23 November), according to experts at Strategic Sentinel, a Washington DC-based nonpartisan geostrategic consulting agency. Experts have previously observed that such transmissions often precede major weapons tests by Pyongyang.

Strategic Sentinel tweeted that it had observed Pyongyang transmitting the coded messages on the North Korean radio station 6400kHz. The radio station has reportedly been used previously by the reclusive nation to send secret coded messages, presumably to spies located outside its borders.

"DPRK says Happy Thanksgiving America by sending coded messages on 6400kHz this morning. DPRK has been very silent the past 2 or so months with infrequent coded messages," Strategic Sentinel wrote in a post.

"DPRK pretty much owns the frequency 6400kHz. That is called Radio Pyongyang and they transmit news, weather, propaganda and music on this frequency nearly 24/7," Strategic Sentinel founder and CEO Ryan Barenklau told IBTimes UK.

"When they decide to transmit coded messages it usually is at the tail of a programme. In a very nonchalant way the programmer will say something like, 'Please turn to page 247 and complete the math questions for sections 5-8.' Now that is just a sample and it changes all the time. There really is no set amount of messages, it is completely random and can include many different phrases or subtle catches," Barenklau added.

It still remains unclear whether the recently transmitted codes were meant as an alert for a possible upcoming missile launch or weapons test. It is also uncertain whether the Kim Jong-un-led regime intended the messages to be some form of instructions for spies residing in foreign nations.

"We cannot be for certain what these messages are saying, what they are for, or whom they are intended for, but many analysts believe the messages are in the realm of these examples: To tell their operators in the field/embassy of upcoming events, updates inside the regime, military moves they wish for those operators to complete, or clandestine moves they wish them to complete," Barenklau told us.

Some cybersecurity experts suspect that Pyongyang may have stationed elite hackers in various Asian nations, including India, to ensure that the regime's cybercriminal activities are harder to detect and deter. Such coded messages could likely be an effective means by which Pyongyang could communicate with its agents abroad.

"This specific time it does not appear so, but we have monitored patterns in the past which could be indicative of missile tests. Sometimes Pyongyang will send out coded messages a few days to a week before a test, but usually a testing cycle must start before that occurs," Barenklau told us when asked whether the recently radioed out coded messages could hint at a possible imminent weapons test.

"DPRK coded messages are more or less a routine thing from the regime. At times they are more important than others. This specific time would fall in the latter category," Barenklau added.

Just last week, 6400kHz, the radio station used to transmit the coded messages, was hijacked by hackers to play the 1980's hit song The Final Countdown.

This article has been updated to include Strategic Sentinel founder and CEO Ryan Barenklau's responses.