The company even admitted that "abnormal activities" had been detected.

The hacked accounts belong to "high ranking officials" in the presidential office, the cabinet, the military, members of the ruling and opposition parties, and regional government chiefs, the Liberty Times reported, citing unnamed sources as quoted by Channel News Asia.

The Criminal Investigation Bureau confirmed it had begun investigating after LINE formally reported the case to authorities on Tuesday, but did not provide further details, reports the news portal.

Taiwan's cybersecurity agency says the island faces an estimated 30 million cyber attacks every month, around half of them believed to originate from China, reports CNA.

Line said in a statement that it has taken necessary measures to protect users.

"We will continue to take necessary responsive measures," the company said in a statement as quoted by CNA.