Nobuyuki Baba, leader of opposition Nippon Ishin no Kai, announced on Sunday that his party will not cooperate with the administration of Prime Minister Shigeru Ishiba.

In a meeting at the prime minister's official residence, Baba told Ishiba, who is also president of the ruling Liberal Democratic Party, that Nippon Ishin cannot work with the Ishiba government on enacting the budget and other bills. He explained that the ruling side had failed to keep its promises, including one to establish a rule requiring the disclosure of how lawmakers use research, public relations and accommodation allowances, which was supposed to be addressed during this year's regular parliamentary session.

At a news conference after the meeting, Baba said he told Ishiba that Nippon Ishin "has no intention at all" to listen to the LDP and "will never make concessions" unless the issue of politics and money is resolved.

A special session of the Diet, the nation's parliament, is set to start Monday following the Oct. 27 general election.

In the House of Representatives election, the LDP and its Komeito ally lost their majority in the all-important lower chamber of the Diet, although the LDP remained the biggest force in the body.