Vietcombank sold the greenback at VND26,344, up 0.02% over the weekend. On the black market, the currency jumped 0.68% to around VND27,950.
The State Bank of Vietnam increased its reference rate by 0.02% to VND25,090.
Globally, the dollar rose on Monday as escalating retaliatory threats in the Middle East conflict curbed risk appetite and lifted demand for safe-haven assets, Reuters reported.
The dollar index, which measures the U.S. currency against a basket of peers, advanced 0.08% to 99.62 after posting a weekly decline last Friday, its first since the start of the war in late February.
The euro slid 0.16% to $1.1552, as the yen weakened 0.14% to 159.45 per dollar. Sterling fell 0.06% to $1.3331. The Australian dollar weakened 0.43% versus the greenback to $0.6993, and New Zealand's kiwi fell 0.26% to $0.5819.
Before the war, investors had priced in two cuts by the Federal Reserve this year. But even one cut is now considered a distant prospect, and other major central banks are turning more hawkish.
"If markets price a U.S. tightening cycle, the USD will lift strongly against all currencies in our view," Joseph Capurso, head of international economics at the Commonwealth Bank of Australia, wrote in a note.