SOUTH Korean assets tumbled after the country’s president declared martial law, sparking investor concern about political instability and unrest.

The iShares MSCI South Korea ETF sank 5.1% in US trading, its worst intraday drop since Aug. 5. The won fell to its weakest level against the US dollar in more than two years. The London-listed shares of Samsung Electronics lost 5%.

President Yoon Suk Yeol said the decision was made to protect freedom and constitutional order, and that it will not have an impact on South Korea’s foreign policy. He added that it would also help remove North Korea supporters.

“The domestic uncertainty adds to the external pressures in recent weeks as the market is starting to price in the rise of higher US tariffs under the new Trump administration,” said Aroop Chatterjee, a strategist at Wells Fargo in New York.

Other South Korean ADRs also declined. E-commerce company Coupang Inc. fell as much as 6.9% in US trading, alongside losses in steel processor Posco Holdings Inc. and KB Financial Group Inc.

The won was the worst among 31 major currencies tracked by Bloomberg, falling 1.7% to 1,430 per dollar.  –BLOOMBERG