FILE PHOTO: Fumio Kishida, Japan's outgoing Foreign Minister and ruling Liberal Democratic Party's new policy chief, arrives at prime minister Shinzo Abe's official residence in Tokyo, Japan, August 3, 2017. REUTERS/Toru Hanai/File Photo

TOKYO (Reuters) - Former Japanese Foreign Minister Fumio Kishida on Tuesday ruled out running in a ruling party leadership race and said he would give his support to Prime Minister Shinzo Abe instead, reinforcing Abe’s chances of staying in power.

Being head of the ruling Liberal Democratic Party (LDP) means Abe would automatically stay on as prime minister since the ruling coalition holds a majority in parliament.

“I decided it was appropriate to deal with various policy challenges under Prime Minister Abe,” Kishida, the LDP’s policy chief, told a news conference.

If Abe is re-elected and his party stays in power, Abe can stay premier until September 2021. Combined with his previous two-year tenure to 2007, that would make him the longest serving leader of Japan.

Kishida has been less popular than other candidates, including Abe, in opinion polls on who should be next prime minister. Analysts have said Kishida may decide not to challenge Abe and wait for the premier to hand-pick him as successor.

Despite being mired in a series of scandals, Abe’s poll ratings have recovered and he is now seen as having a strong chance of winning a third term as LDP head.

With Kishida out of the race, contenders challenging Abe would include ex-defense minister Shigeru Ishiba, Internal Affairs Minister Seiko Noda and Foreign Minister Taro Kono.