The opposition Nippon Ishin Japan Innovation Party has decided to expel Suzuki Muneo, who recently visited Russia without submitting a prior notification and is believed to have made controversial remarks there.

The party's executive board made the decision on Tuesday after its ethics committee said Suzuki's behavior disturbed party discipline.

Suzuki, an Upper House lawmaker, visited Russia and met with Deputy Foreign Minister Andrey Rudenko in Moscow on Monday of last week.

Participants at the party's executive meeting last week pointed out Suzuki failed to present a notification for the travel.

They also said they confirmed the existence of a video taken during the visit in which Suzuki said he is confident about Russia's victory in its invasion of Ukraine. Some of the attendants called for a strict punishment on him.

The party appears to have decided to expel him because Suzuki has shown intent to visit Russia again despite its leadership's instruction of refraining from traveling there.

But the party says his controversial remarks are not included in the reasons for the expulsion.

Suzuki previously said the notification was delayed due to a clerical mistake and that he would accept a punishment. He also indicated he might file a lawsuit if he were punished for his remarks.