S.Korea won tumbles to 4-week low, shares slide on rising US-N.Korea tensions

* Trump warns "fire and fury" for North Korea if it threatens U.S.

* Won drops nearly 1 pct to lowest since mid-July

* KOSPI slides 0.8 pct; foreign investors set to be net sellers

SEOUL, Aug 9 (Reuters) - The South Korean won sank to a four-week low and shares fell on Wednesday after North

Korea said it is considering plans for a missile strike on the U.S. Pacific territory of Guam. The statement came just hours after President Donald Trump told the North that any threat to the United States would be met with "fire and fury," rattling global financial markets.

The Korea Composite Stock Price Index (KOSPI) was

down 0.8 percent at 2,375.59 points by 0047 GMT. It fell to as low as 2,376.62 soon after the open.

The won sank around 0.8 percent to 1,133.8 to the

dollar, its weakest intraday level since July 14. But shares of defense-related companies rose, with LIG Nex1

Co Ltd up nearly 5 percent and Firstec

up 3 percent. Washington has warned it is ready to use force if need be to stop North Korea's ballistic missile and nuclear programs but that it prefers global diplomatic action, including sanctions. The spread on South Korea's 5-year credit default swaps stood at 56.4 basis points and risk reversals in

won options at 1.2 points, both well below their last

highs seen in April.

(Reporting by Dahee Kim; Editing by Kim Coghill)