Katsuya Okada, president of the Democratic Party, said he will not resign immediately over the party's disappointing showing in the Upper House election and failure to prevent forces in favor of constitutional reform from securing a two-thirds majority.

The party appears to have derived some benefit from its unprecedented electoral alliance with the Japanese Communist Party and two other opposition parties that coordinated the fielding of candidates in single-seat districts, with Okada saying late Sunday he hopes to carry over such cooperation to the next general election.

The Democratic Party suffered a decline from the 60 seats it held in the 242-member chamber prior to the election, while the JCP ended with three more seats at 14.