TOKYO, Aug 23 (Reuters) - Japan"s former Foreign Minister Fumio Kishida is likely to run in the ruling party"s leadership race when incumbent Yoshihide Suga"s current term ends in September, the Sankei newspaper reported on Monday. Kishida is likely to formally announce his candidacy when the date of the ruling Liberal Democratic Party"s (LDP) leadership race is fixed, the paper said, citing several anonymous sources. The party will decide on Thursday when to hold the race, with the most likely date seen as Sept. 29, the paper said. An ally of Suga backed by the LDP lost a mayoral race in Yokohama on Sunday, Japanese media reported, in a blow to prime Suga, who has seen his popularity plunge due to his handling of the COVID-19 pandemic. read more Suga"s low ratings have heightened calls within the LDP to pick a new face in the party leadership race ahead of a general election that must be held by Oct. 21. read more Kishida has been considered a strong candidate for the top LDP role. Former general affairs minister Sanae Takaichi and ruling party executive Hakubun Shimomura have also expressed interest in running, according to media reports.