Prime Minister Shinzo Abe's Liberal Democratic Party decided Thursday to convene its leadership race as originally scheduled despite a strong earthquake hitting Hokkaido earlier in the day, its senior lawmaker said.

Official campaigning will kick off Friday for the election on Sept. 20 in which only Abe and former Defense Minister Shigeru Ishiba are expected to file their candidacies.

Following the extensive damage caused by the quake, the LDP postponed a news conference by the contenders planned for Friday, Secretary-General Toshihiro Nikai told reporters.

The ruling party will also refrain from holding campaign events, including debate sessions and campaign speeches, for a few days to focus on responding to the disaster, Nikai said.

In the LDP leadership race, Abe is widely expected to beat Ishiba with the support of a majority of party lawmakers.

The winner of the party presidency is certain to assume the post of prime minster as the LDP-led ruling bloc controls both houses of the Diet. With another three-year term as LDP chief, Abe would be in a position to become Japan's longest-serving prime minister.

Separately, Chief Cabinet Secretary Yoshihide Suga said Thursday there is no change in Abe's plan to travel to Russia next week. He is scheduled to visit Russia from Monday to Thursday to attend an international economic forum, and looks to hold bilateral talks with Russian President Vladimir Putin and Chinese President Xi Jinping.