TOKYO, Oct 3 (Reuters) - Japan's Nikkei share average slumped to a four-month low on Tuesday as sentiment soured amid higher U.S. yields and the Federal Reserve's pledge of an extended period of tight financial conditions.

The Nikkei extended losses in the afternoon, dipping as low as 31,157.40 for the first time since June 1 before closing 1.64% lower at 31,237.94.

Of the index's 225 components, 211 fell, with 11 gaining and three flat.

The broader Topix slipped about 1.68%.

The benchmark 10-year Treasury yield marched to a fresh 16-year peak above 4.7% overnight after Fed Governor Michelle Bowman and Fed Vice Chair for Supervision Michael Barr reiterated the higher-rates-for-longer refrain at separate events.

The rise in long-term U.S. yields helped push the yen to the lowest in a year at close to 150 per dollar, but that failed to help lift Japanese exporter shares.

Toyota Motor sagged 3.05% and Mazda sank 6%.

"Normally yen weakness would be a reason for stocks to rise, particularly the exporters, because it boosts overseas profits," said Nomura Securities strategist Maki Sawada.

"But because the background for the move is a rise in long-term yields, it's a weight on the Nikkei."

The promise of extended tight financial conditions also weighed on crude oil, which tumbled 2% overnight.

As a result, resource shares were the worst performers. Among the Tokyo Stock Exchange's 33 industry groups, mining paced declines with a 6.26% plunge, followed by a 5.47% drop for oil and coal producers.

Refiner Inpex was the worst-performing Nikkei stock, sagging 6.49%. Peer ENEOS Holdings lost 5.86%, while JGC Holdings, an engineering company also involved in the oil business, dropped 5.79%.

Tech stocks provided some relief, helped partly by the Nasdaq's outperformance overnight on Wall Street.

Online services providers LY Corp and Recruit Holdings rose 1.31% and 0.33% respectively, while Nintendo gained 0.49% and Sony Group added 0.45%. (Reporting by Kevin Buckland; Editing by Sohini Goswami)