A growing number of lawmakers within the ruling Liberal Democratic Party are saying they would back Chief Cabinet Secretary Yoshihide Suga in a vote to choose the successor to outgoing Japanese Prime Minister Shinzo Abe, thrusting him to the forefront of the party's leadership race.

Suga on Monday told lawmakers close to him that he is "optimistically" considering a run. According to people familiar with the matter, the top government spokesman intends to announce his candidacy after the party formally decides Tuesday to hold the election on Sept. 14.

A 47-member faction within the LDP led by Secretary General Toshihiro Nikai has finalized plans to endorse Suga, while another headed by Finance Minister Taro Aso is expected to do the same, according to people privy to the matter.

Combined photo taken in July 2019 shows (from L) Japanese Chief Cabinet Secretary Yoshihide Suga, Liberal Democratic Party policy chief Fumio Kishida and former LDP Secretary General Shigeru Ishiba. (Kyodo) 

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Aso, a longtime Abe ally who himself held the premiership from 2008 to 2009, has said he will throw the support of his 54-member faction behind whoever can best implement policies that align with his thinking.

A group of lawmakers met with Suga on Monday and urged him to join the race, which LDP policy chief Fumio Kishida has already entered.

Earlier in the day, Kishida met with Abe at the prime minister's office and asked for his support in the leadership race, which was triggered by Abe's sudden announcement Friday he is stepping down to receive treatment for a chronic intestinal illness.

Abe has delegated the matter of how to hold the election to Nikai, who according to a senior LDP lawmaker plans to limit voting to standing Diet members and representatives of the party's local chapters, with rank-and-file members being left out in order to expedite the process.

But some within the LDP expressed dissatisfaction with the decision, with more than 140 lawmakers including former Defense Minister Shigeru Ishiba signing a petition for a full election to be held to give the new prime minister a strong mandate.

Ishiba, who leads a faction with 19 members and was Abe's lone competitor in the 2018 election, has also indicated he is considering a run. A Kyodo News survey on Sunday showed Ishiba to be the most popular choice for Japan's next leader, but he lags behind rivals in support from lawmakers and would be greatly disadvantaged by the exclusion of rank-and-file members from voting.

Other potential contenders include Defense Minister Taro Kono and Foreign Minister Toshimitsu Motegi. Meanwhile, economic and fiscal policy minister Yasutoshi Nishimura, who is spearheading the government's response to the coronavirus pandemic and ran in 2009, said Monday he will not stand in the upcoming election.