Brent crude futures fell 71 cents, or 0.9%, to $84.00 a barrel by 0450 GMT, after dropping to a session-low of $83.27 earlier.
U.S. West Texas Intermediate (WTI) crude futures tumbled $1.10, or 1.3%, to $82.81 a barrel, after dropping to a low of $82.26 earlier.
"Crude prices are declining after the API reported the sixth straight week of crude oil inventory builds and as the Biden administration exhausts every possible plea to OPEC+ members before tapping their Strategic Petroleum Reserve," said Edward Moya, senior analyst at OANDA.
"World leaders are running out of cards to pressure OPEC+ and that should mean whatever dip that comes from tapping strategic reserves from China or the US will likely be bought into."
President Joe Biden, speaking at a climate summit in Glasgow, blamed a surge in oil and gas prices on a refusal by OPEC nations to pump more crude. read more
OPEC+ meets on Thursday to review its policy and is expected to reconfirm plans for monthly increases. read more