SEOUL: South Korea's foreign exchange authority was spotted selling US dollars on Monday to limit a decline in the won currency, traders said, after a warning that it was monitoring speculative movement in the offshore market.

The won gave up as much as 1.1% to stand at 1,227.6 against the dollar, its lowest since June 1, 2020, after closing the previous session at 1,214.2.

"It is suspected that there was an (FX) intervention," said one trader, who spoke on condition of anonymity, while adding, "It was not enough to overwhelm the market."

The won retreated to 1,226.1 per dollar after the authority said it was "monitoring whether there is any speculative movement in the offshore market or excessive anxiety among local market participants due to recent changes in external conditions," in a text message it sent to Reuters.

The reference was to the escalating Ukraine crisis.

"We will strengthen communication with major FX players in the local market," it added.

The finance ministry and central bank made comments via text message to some reporters regarding spot movements in FX markets in cases of sharp volatility.