Vietcombank sold the greenback 0.02% higher at VND26,315. But on the black market the dollar surged 1.12% to VND27,200.
Globally the dollar lost some of its safe-haven appeal on speculation that the war in the Middle East could prove limited on Tuesday, pulling down skyrocketing oil prices and boosting risk assets, Reuters reported.
At 157.73 yen and $1.1632 per euro, the greenback was firm in early Asia trade, but it has retreated from day-earlier highs after U.S. President Donald Trump said war against Iran was "very complete."
Washington was "very far ahead" of his initial four- to five-week time estimate, he told CBS News.
Sterling recovered from a Monday dip to hold at $1.3412 and the New Zealand dollar steadied at $0.5932.