North Korea aired a broadcast of encrypted numbers on Friday, apparently aiming at sending messages to spies operating in South Korea.

The coded radio broadcast began at 1:15 a.m. by the North's propaganda radio station Radio Pyongyang. The broadcast lasted for approximately 5 minutes.

The announcer then said, "On page 428 number 51, on page 192 number 33, on page 260 number 41," followed by more numbers. 

The latest batch of numbers were the same as the broadcast made on Jan. 13.

It marked the fourth time for Pyongyang to air encrypted numbers this year, and the 24th time since June 2016. (Yonhap)