Japan's ruling Liberal Democratic Party (LDP) Secretary General Taro Aso formally announced his decision Friday afternoon to run in the party's presidential election, according to Kyodo News.
The former foreign minister declared his candidacy at a press conference in Tokyo.
Former Chief Cabinet Secretary Yasuo Fukuda in the morning expressed his intention to run in the election at a temporary meeting of a party faction he belongs to.
Finance Minister Fukushiro Nukaga, who showed willingness to seek the party leader's post, decided on Friday to give up after exchanging ideas with Fukuda and decided to support him.
The upcoming competition will be a battle between Aso and Fukuda. The latter enjoys obvious advantage in the rival since over a half of the LDP factions have decided to extend support for him, Japan's television network NHK reported.
The LDP decided on Thursday at its General Council meeting to hold the presidential election on Sept. 23 to pick a new president to replace Shinzo Abe, who expressed his intention to resign on Wednesday. It announced on Friday the formalities of the leadership election and will accept candidacies on Saturday.
Former Prime Minister Junichiro Koizumi on Thursday turned down junior followers' request and ruled out the possibility of his running in the election.
Endorsement by at least 20 LDP lawmakers is needed for being accepted as a candidate for the LDP presidential election.
Since the LDP enjoys the majority in the lower house, or the House of Representatives, which holds the decisive power in the Diet, the LDP president will be naturally appointed prime minister.
Abe was elected the 21st LDP president on Sept. 20, 2006, and was appointed prime minister by the lower house six days later.