The US Army has sent Bradley fighting vehicles to eastern Syria (Picture: Twitter/ OIRSpox).
The Pentagon says the United States is not profiting from Syrian petroleum, despite having deployed troops to protect oil fields in the east of the country.
An official told reporters in Washington that the revenue was going to the Kurdish-led Syrian Democratic Forces (SDF), not the United States.
Pentagon spokesman Jonathan Rath Hoffman said US troops had been deployed in eastern Syria to prevent the so-called Islamic State group (IS) fighters from acquiring the wells.
Navy Rear Admiral William D. Byrne Jr, Vice Director of the Joint Staff, IS was in control of the oil infrastructure in Syria in 2015 and was producing 45,000 barrels a day — worth approximately $1.5 million.
Mr Hoffman said the US "want to prevent" IS using oil money to fund worldwide terror operations.
Russia's defence ministry has previously criticised the US decision to send armoured vehicles and combat troops to oil fields, calling the move "international state banditry".
The Kremlin agreed a conditional ceasefire deal with Turkey, securing 'safe-zones' across Syria's northern border - free from the Kurdish militia Turkey considers terrorists.
Mr Hoffman listed two reasons for securing the infrastructure: "It's preventing ISIS from getting it... while at the same time allowing the Kurds and the SDF to have control of it, as well," he said.