Radio Free Asia says that a U.N. agency has activated surveillance of North Korea amid forecasts that the communist state could conduct its third nuclear test very soon.

A deputy spokesman of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) says that North Korea is being monitored around the clock at observation facilities worldwide. The official says a nuclear test by the North can be immediately detected, as was the case in 2006 and 2009.

He said North Korea was being watched with regards to its nuclear test activity at some 300 observation posts and 16 laboratories around the world using methods involving seismic waves, underwater sound waves, ultra-low frequency and nuclear material analysis.

He adds that once signs of a nuclear test are detected, this will be conveyed to the UN Security Council and 182 member countries within an hour.