Crude oil prices edged lower on Tuesday, with traders taking some profits after recent strong gains, and looking ahead to weekly inventory reports.
Oil prices moved higher early on in the session amid optimism that OPEC and non-OPEC countries including Russia, would agree to extend production cuts in a bit to support prices.
Prices fell after U.S. President Donald Trump announced the sacking of national security advisor John Bolton. Trump wrote on Twitter that Bolton "disagreed strongly with many of his suggestions."
A section of the market appears to believe the exit of Bolton might result in the Trump administration reviewing the sanctions imposed against Iran.
West Texas Intermediate Crude oil futures for October ended down $0.45, or about 0.8%, at $57.40 a barrel.
On Monday, WTI crude oil futures ended up $1.33, or 2.4%, at $87.85 a barrel, after having gained about 0.4% a session earlier.
Saudi Arabia's new energy minister, Prince Abdulaziz bin Salman, said on Monday that the pillars of Saudi Arabia's policy would not change and a global deal to cut oil production by 1.2 million barrels per day would continue.
In his first public appearance since being appointed energy minister, Abdulaziz said that the deal agreed a year ago by major oil producers to limit output was "until death do us part."
The American Petroleum Institute will release its weekly oil report later this evening, while the Energy Information Administration is scheduled to release its inventory data at 10:30 AM on Wednesday.