In this June 12 photo, North Korean soldiers look at the South side, seen during a press tour at the Panmunjom in the Demilitarized Zone, South Korea. AP

North Korea has banned tours to the northern side of the Demilitarized Zone (DMZ), a Beijing-based tour agency said Sunday, an indication that the restriction was part of security measures for a possible meeting between leader Kim Jong-un and U.S. President Donald Trump.

"The DMZ is closed to tourists visiting from the North Korean side today," Koryo Tours, specializing in trips to North Korea, said in a tweet without providing more details.

Trump and South Korean President Moon Jae-in plan to travel to the DMZ after their summit in Seoul. At the start of talks with Moon, Trump said that preparations for a meeting at the DMZ were in the final stage.

"I have been told that Kim Jong-un would like to meet, and that it looks like they are in the final stages of working out just a very quick meeting because I will be at the DMZ," he said.

Hours after Trump expressed his desire for a DMZ meeting with Kim on Saturday, North Korea called the proposal a "very interesting suggestion." (Yonhap)