Japanese Prime Minister Shigeru Ishiba vowed to remain in office on Monday after his ruling coalition suffered a bruising defeat in upper house elections, as the opposition weighed a no-confidence motion.

Ishiba's ruling Liberal Democratic Party and its junior coalition partner Komeito were short three seats to maintain a majority in the 248-seat upper house in Sunday's vote.

By John Geddie and Tim Kelly TOKYO (Reuters) -Japanese Premier Shigeru Ishiba vowed to remain in his post on Monday after his ruling coalition suffered a bruising defeat in upper house elections, prompting some in his own party to doubt his leadership as the opposition weighed a no-confidence motion.