Dollar dips against dong

Vietcombank sold the greenback at VND26,385, a 0.008% drop over the weekend. On the black market, the currency dropped 0.29% to around VND26,877.

The State Bank of Vietnam raised its reference rate by 0.008% to VND25,129.

Globally, the U.S. dollar retreated from its strongest in a month early on Monday, as U.S. prosecutors opened a criminal investigation into Federal Reserve Chair Jerome Powell, adding to tensions with the Trump administration, Reuters reported.

The dollar index, which measures the greenback's strength against a basket of six currencies, was last 0.3% lower at 98.899, snapping a five-day winning streak.

"This open warfare between the Fed and the U.S. administration -- and to the extent that you take Powell's comments at face value -- it's clearly not a good look for the U.S. dollar," said Ray Attrill, head of FX strategy at National Australia Bank in Sydney.

Against the yen, the U.S. dollar was last 0.2% lower at 157.56 yen, edging back from its strongest in a year. The Australian dollar strengthened 0.2% to $0.6704, while the New Zealand dollar was 0.2% firmer at $0.5746.

The euro was last 0.2% stronger at $1.1664 while the British pound nudged up 0.2% at $1.3433, both rebounding from a one-month low. The U.S. dollar was 0.1% weaker against the Chinese yuan trading offshore in Hong Kong at 6.968 yuan, its softest in a week.