Brent crude futures rose 1.2 percent to $77.72 a barrel by 08:37 GMT. The dollar rose to its highest level in two months against a basket of major currencies, as negotiations on raising the US debt ceiling protracted.
Saudi Energy Minister Prince Abdulaziz bin Salman said he would keep speculators betting prices falling "in pain" and called on them to be "cautious" Some investors saw this as a sign that the OPEC Plus alliance could discuss further production cuts at a meeting on June 4.