The dollar hovered near a two-month high on Wednesday as investors flocked to the safe-haven currency as debt ceiling talks in the United States continued to stall.
And US Treasury Secretary Janet Yellen warns that the federal government may not have enough money to pay all its obligations by June 1.
Investors are largely shying away from riskier investments after a new round of talks between the White House and Republicans on Tuesday to raise the debt ceiling ended without any sign of progress.
The dollar index, which measures the greenback against six rival currencies, reached 103.51 in early trading hours in Asia, just below the two-month peak the index touched overnight at 103.65. The index rose nearly 2 percent in May.
The yen settled at 138.58 per dollar, after touching a six-month low of 138.91 overnight, while the pound sterling rose in the latest trading by 0.11 percent to $1.2424.