The race to succeed Japanese Prime Minister Shinzo Abe shaped up on Friday as a fight between 71-year-old lawmaker Yasuo Fukuda, an advocate of warm ties with Asian neighbors, and hawkish former foreign minister Taro Aso.

Fukuda emerged as the frontrunner after several ruling Liberal Democratic Party (LDP) factions threw their support behind him, but the outspoken Aso vowed to fight to the end.

Japanese media said Abe's predecessor, Junichiro Koizumi, was backing Fukuda while a Kyodo news agency poll said voters favored Fukuda 28.1 percent to 18.7 percent for Aso.