SEOUL, Jan. 11 -- South Korea said on Monday that it will restrict the entry of South Korean workers into the inter-Korean industrial complex in the Democratic People's Republic of Korea's (DPRK) border city of Kaesong after Pyongyang's nuclear test.

Unification Ministry spokesman Jeong Joon-Hee told a regular press briefing that workers to be allowed to stay in the Kaesong factory park will be lowered to the minimum level necessary for production on Tuesday.

Jeong said the minimum number will be adjusted from the current 800 people or so to about 650. Some 120 South Korean companies run factories in the Kaesong complex, employing tens of thousands of DPRK workers.

The entrance restriction came after the DPRK said last Wednesday that it had successfully tested its first hydrogen bomb.

In retaliation for the nuclear test, South Korea's military resumed blaring propaganda messages from loudspeakers on Friday across the border into the DPRK, which had called it an "act of declaring war."

Jeong said DPRK countermeasures were expected after the resumption of loudspeaker broadcasts in border areas, expressing worry about possible provocations.

In August 2015 when South Korea's military restarted the broadcasts in response to what Seoul claimed were land mine explosions planted by DPRK forces, it took just 10 days to trigger an exchange of artillery fire across the border between the two Koreas.