A clerk sorts $100 banknotes at the headquarters of Hana Bank in Seoul, Thursday. Yonhap

The Korean won tumbled to the lowest level since 2009 against the U.S. dollar Friday, as foreign investors continued to sell local stocks amid fading expectations of a diplomatic solution to the war in the Middle East.

The won was quoted at 1,539.1 won per dollar at 3:30 p.m., down 9.4 won from the previous session, marking the weakest level since March 9, 2009.

The won opened at 1,529 won per dollar, up 0.7 won from the previous session's close, but lost ground as foreign investors offloaded local shares.

At one point in Friday trading, the won weakened to 1,549.1 won per dollar, marking the weakest level in terms of an intraday trading since March 10, 2009.