Japan's Prime Minister Shigeru Ishiba announced Sunday he will step down following growing calls from his party to take responsibility for a historic defeat in July's parliamentary election.

Ishiba, who took office in October, had resisted demands from mostly right-wing opponents within his own party for more than a month, saying such a step would cause a political vacuum when Japan faces key challenges in and outside the country.

The resignation came one day before his Liberal Democratic Party (LDP) was to decide whether to hold an early leadership election, a virtual no-confidence motion against him if approved.