A Japanese media outlet said that North Korea is significantly increasing activity at its nuclear test site, including the installation of an observatory facility. 

Kyodo News reported Sunday quoting government sources in Seoul and Tokyo that it is possible North Korea will conduct a fifth nuclear test as early as this month.

A South Korean government official was quoted by Kyodo as saying that the activities observed over the past week at the North’s Punggye-ri nuclear test site has been the most brisk in recent months.

The Japanese paper said that the South Korean government sees that Pyongyang is ready to conduct a nuclear test anytime.

Since its fourth nuclear test in January, the regime has been observed preparing for another nuclear test, but the speculation over the fifth nuclear test has been rising since the Seoul-Washington alliance’s decision to deploy a Terminal High Altitude Area Defense in South Korea.

Two days after the THAAD deployment decision was made, Pyongyang threatened to launch “physical action” against South Korea and the U.S.