The South Korean won weakened on Thursday after the central bank cut its policy rate to a record low and downgraded 2020 growth forecast, while most other Asian currencies also slipped as Sino-US tensions over Hong Kong escalated.
The won led declines in the region, falling as much as 0.7% to 1,242.50 per dollar, its worst intraday performance in more than three weeks.
The Bank of Korea cut its benchmark interest rate by a quarter of a percentage point to 0.5% as it warned the coronavirus pandemic would be worse for Asia's fourth-largest economy than the 2008 global financial crisis.
Asian currencies came under pressure as a rift between the world's two top economies worsened. US Secretary of State Mike Pompeo said on Wednesday Hong Kong no longer qualified for its special status under US law.
The Chinese yuan was little changed at 7.166 per dollar in onshore trade, while its offshore counterpart hovered close to a record low of 7.1966 struck overnight.
The Philippine peso dropped 0.2%, while the Singapore dollar largely wavered. The Malaysian ringgit and the Indian rupee eased 0.2% and 0.1%, respectively.
The Indonesian rupiah weakened 0.4%, in line with its peers.