Police said Monday they have been cracking down on the spread of fake news involving such sensitive issues as the presidential impeachment, North Korea's military action and US President Donald Trump's alleged bias against Korean liberals.

The National Police Agency began last month to monitor fraudulent news on the Internet and carried out an investigation into 40 cases. It requested the country's communications watchdog delete or block 19 of them and continued to look into five others.

The fake news blocked or deleted by the Korea Communications Standards Commission included what appeared to be reports on US cable broadcaster CNN with Korean subtitles such as "North Korean troops are advancing on (South Korea's presidential office) Cheong Wa Dae" and "US President Donald Trump said he won't talk to the Jeolla provinces."

Jeolla, which comprises the southwestern region of South Korea, is associated with the country's liberal opposition bloc.

The fake news reports still under investigation include a posting that falsely claimed 80 percent of the population was in favor of the Constitutional Court dismissing the impeachment of Park Geun-hye as president.

Police also reviewed the illegality of various fake news reports printed by Park's supporters in the weeks leading to her ouster Friday.

"An online media outlet can be fined for printing newspapers, but the Ministry of Culture, Sports and Tourism, which is the department in charge, says it has never levied such fines," a police official said, indicating there is little the police can do.

Police have also been monitoring recent online postings threatening the court's then acting chief, Lee Jung-mi, over the ruling on Park's removal.

They plan to launch an investigation after determining whether the threats are specific and likely to be realized. (Yonhap)