U.S. oil prices rose nearly 3 percent on Monday as polls showing a lower likelihood of Britain leaving the European Union weakened the dollar, boosting commodities priced in the U.S. currency.
Data from market intelligence firm Genscape pointing to a drawdown of 568,213 barrels at the Cushing, Oklahoma delivery base for U.S. crude futures in the week to June 17 also helped sentiment, said traders who saw the numbers.
August Brent crude futures were up $1.38, or 2.8 percent, at $50.55 a barrel. The contract has risen more than 6 percent since Thursday's settlement, after falling 10 percent in six previous sessions.
U.S. crude for July delivery, which expires on Tuesday, settled 2.9 percent higher, or $1.39, at $49.37. But the contract, which expires on Tuesday, was barely traded, with volume flocking to nearby August, which will be the next front-month for WTI.