Brent futures were down 86 cents, or 0.8%, at $107.92 a barrel, while US West Texas Intermediate CLc1 futures were off $1.10 or 1.1%, at $103.15 a barrel at 1335 GMT.
"The market was less active than usual, due to the long weekend in Europe, America and most of Asia, with the reduction in the number of active buyers also contributing to the easing in prices," said Ricardo Evangelista, senior analyst at ActivTrades, citing the US stock build. The International Energy Agency on Wednesday warned that from May onwards roughly 3 million barrels per day of Russian oil could be shut-in due to sanctions or buyers voluntarily shunning Russian cargoes.