Oil prices fell after industry data showed that US inventories of crude rose unexpectedly, with the new month starting to drop after it suffered its biggest monthly loss in two years in July.
Brent crude for October delivery fell 30 cents, or 0.4 percent, to $ 73.91 a barrel by 0325 GMT, up 1.8 percent in the previous session.
US benchmark WTI fell 37 cents, or 0.5 percent, to $ 68.39 a barrel after falling nearly 2 percent on Tuesday.
The Brent crude fell more than 6 percent in July, while US crude fell nearly 7 percent, the biggest monthly drop for record highs since July 2016.
Data from the US Petroleum Institute showed an increase of 5.6 million barrels in crude oil inventories in the United States last week, while a Reuters poll expected 2.8 million barrels to fall.
The US Energy Information Administration is expected to release its inventory data on Wednesday.
Traders said signs of a possible solution to a temporary disruption of oil shipments across the Bab al-Mandab Strait at the southern entrance to the Red Sea had an impact on prices throughout the session.