Four activists have been referred to trial on charges of violating the National Security Act.

The Seoul Central District Prosecutors Office indicted the four suspects on Wednesday, saying they organized a criminal group in line with North Korea's unification policies, contacted North Korean spies overseas and received orders and operational funds from them.

The prosecution said it confirmed that the suspects executed orders from Pyongyang to hold anti-government and anti-U.S. labor rallies, civic protests and candlelight vigils.

One of the four who runs a shoe manufacturing company is accused of contacting North Korean agents in foreign countries including Cambodia and Vietnam four times between 2016 and 2019.

Prosecutors believe that in one such meeting in Cambodia in June 2019, a letter of allegiance was delivered to a North Korean agent who handed over seven-thousand dollars in operational expenses.

The four are suspected of working for an alleged pro-North Korea spy ring based in Changwon.