Prime Minister Junichiro Koizumi said Thursday he will leave his post and step down as president of the Liberal Democratic Party if the three-party ruling coalition fails to retain a majority in the Nov. 9 House of Representatives general election.

The 61-year-old Koizumi, who recently prevailed in rocky efforts to get former Prime Minister Yasuhiro Nakasone, 85, to retire, revealed that he may retire from politics when he turns 65.

During an interview Thursday, Koizumi said that even if the tripartite coalition loses its majority, his successor would have to decide whether the LDP would try to stay in power, possibly by aligning itself with other parties, if it retains its status as the chamber's largest single party.