A Japanese freelance journalist detained by security forces in Myanmar's largest city Yangon has been investigated for allegedly spreading fake news, the Japanese Embassy in Myanmar said Monday.

Yuki Kitazumi, a former reporter for the Tokyo-based Nikkei business daily who now lives in Yangon, was detained by security forces in Yangon on Sunday, local media reported. The embassy said earlier Monday that Kitazumi was transferred to prison.

Yuki Kitazumi. (Kyodo)

Kitazumi's reports on protests against the Feb. 1 coup in Myanmar have been carried by Japanese media and he has also posted about the situation in the country on social media, which could be regarded as information disadvantaging the ruling military and "fake news."

But the embassy said Kitazumi did not suffer any injuries.

The 45-year-old journalist was also briefly detained by security forces while covering an anti-coup protest in Yangon on Feb. 26.

On Sunday night, he was detained at his house and taken away in a police vehicle, local media reported.

Kitazumi has been moved to Insein prison in Yangon where many political detainees are imprisoned, the embassy said.

Japanese Prime Minister Yoshihide Suga said the embassy is seeking information regarding Kitazumi's detention.

"We will do our best to protect Japanese nationals in the country," Suga told reporters.

Chief Cabinet Secretary Katsunobu Kato said in a press conference, "We are urging the Myanmar government to release the journalist as soon as possible."

According to posts on social media, some people saw Kitazumi forced to raise his hands and kneel down by security forces and they brought out cardboard boxes from his house after searching it.

Local people responded to Kitazumi's detention by saying they wish he is soon freed from security forces.

A social media user named Aung Lin posted a message saying "Release the Japanese reporter immediately!" and another user, Moe Myint, wrote "wishing him to be free from harm and for quick release."

The military has detained many journalists including foreign nationals since the coup that ousted the elected government led by Aung San Suu Kyi. It has also increasingly suppressed free speech by stripping local media companies of their licenses and restricted use of the internet.

The offenses of spreading fake news and fanning social unrest are punishable in Myanmar by up to three years' imprisonment.