Tokyo- Tokyo Governor Yuriko Koike said Thursday that she has submitted a letter of resignation from Japan's ruling Liberal Democratic Party, clarifying her position before becoming leader of Tomin First no Kai (Tokyoites first group), a regional political party.

The LDP is expected to approve her resignation, sources familiar with the situation said.

Koike has now taken more clearly a confrontational stand against the LDP ahead of the Tokyo metropolitan assembly election on July 2, the sources said.

The governor said at a press conference that she decided to submit the resignation letter as the LDP has been putting off its decision on the handling of her LDP membership.

Koike said that she informed LDP Secretary-General Toshihiro Nikai of her intention to leave the party in advance.

Koike ran in the Tokyo gubernatorial election in July last year despite opposition from the LDP. At the time, she asked the party to make a decision on her fate as its member.

On Tuesday, Koike revealed her intention to assume the top post at Tomin First, which she has already been heading effectively, in the run-up to the metropolitan assembly election.

Some LDP lawmakers have criticized Koike, saying that it would be wrong if she becomes Tomin First leader while keeping her LDP membership.

"Of course she should leave the LDP," Hakubun Shimomura, executive acting secretary-general of the ruling party, told reporters on Thursday, after hearing the news on her submission of the resignation letter to the LDP. (Jiji Press)