KOBE (Kyodo) -- Takashi Tachibana, the leader of a Japanese political party known for his controversial remarks, was arrested Sunday on suspicion of defaming a critic of a candidate he backed in the Hyogo gubernatorial election in November last year, police said.

Tachibana, head of the NHK Party that campaigns against Japan's public broadcaster, is accused of repeatedly spreading false information about Hideaki Takeuchi, a member of the Hyogo prefectural assembly.

The police declined to say whether Tachibana has admitted to the allegations.

According to the police, Tachibana, 58, said in a stump speech in December last year that he is "pretty sure" that Takeuchi is "undergoing police questioning."

In January, the NHK Party chief allegedly spread false information on social media and in a different campaign speech, saying Takeuchi is "scheduled to be arrested."

After the claims spread on social media, the prefectural police issued a denial, prompting Tachibana to apologize.

Tachibana's party has a seat in the House of Councillors and the lawmaker has joined a parliamentary group led by the ruling Liberal Democratic Party.

Takeuchi was a member of a special committee that investigated abuse of power allegations against Hyogo Gov. Motohiko Saito, who lost his position after a no-confidence motion was passed by the prefectural assembly but later secured reelection.

Takeuchi resigned as an assembly member after facing abuse on social media. He died in January.

Earlier this year, the widow filed a criminal complaint with the police against Tachibana, calling his claims false.

Tachibana, a former member of the upper house, ran in the Hyogo gubernatorial election, criticizing the committee and saying he was using the opportunity to help Saito.

After the widow filed the complaint, Tachibana wrote on social media that he had told the police during voluntary questioning that there were sufficient grounds for his remarks.

Tachibana was scheduled to hold a press conference on Monday to announce his plan to run for mayor of Ito in Shizuoka Prefecture. The mayoral election is slated for December.

The police said they arrested Tachibana to prevent evidence tampering and called his remarks "groundless."