SINGAPORE (AP) — Singapore police said Friday they arrested two South Korean journalists while investigating a report of trespassing in the residence of the North Korean ambassador.

The statement posted on the police Facebook page said the two men represented the Korean Broadcasting System News but were not accredited as media personnel in Singapore. The broadcaster is more widely known as KBS.

Reacting to the arrest, South Korean presidential spokesman Kim Eui-kyeom pleaded with South Korean journalists in Singapore to act with caution. He said the island state exercises "very strict government power" and that security has been further heightened ahead of the meeting between President Donald Trump and North Korean leader Kim Jong Un on Tuesday.

"If a problem occurs, our government will put in our best diplomatic effort to resolve it, but there could be cases where that wouldn't be enough," Kim, the spokesman, said in a briefing.

The KBS did not immediately respond to a request for comment.

Singaporean police were still investigating two other South Koreans — a representative of the broadcaster and an interpreter-guide.

A criminal trespass conviction in Singapore carries up to three months' imprisonment, a fine of up to $1,500, or both.

Police also said journalists who commit crimes in Singapore will not be accredited and thus will be unable to cover the Tuesday summit.