Emerging Asian currencies came under further pressure as the Chinese yuan fell to a one-year low against the dollar for a record weekly loss. Investors bet on sustained weakness in the renminbi as the central bank's actions indicated it was comfortable with the downtrend.
The rupiah slid on weakness in the non-deliverable forwards markets and on dollar demand from importers.
The Philippine peso fell as much as 0.6 percent to 45.105 per dollar, its weakest level since Feb. 11, amid higher government bond yields after the central bank governor gave a strong hint that interest rates may be hiked soon.
Thailand's baht weakened as local stocks and bonds prices fell.
The Malaysian ringgit slid on proxy plays to bet on a weaker renminbi.
Yellen said on Wednesday the Fed will probably end its bond-buying programme later this year and could start raising interest rates around six months later, dampening stocks and bond prices.