Russia and Iran have criticized Trump's decision to maintain U.S. troops near oil fields in northeastern Syria to exploit the resource.

"It seems that the United States stays behind to protect the oil. At least President Trump is honest about the US intent," Iranian Foreign Minister Mohammad Javad Zarif told a news conference in Geneva, Switzerland, yesterday. when meeting his Russian counterpart Sergei Lavrov and his Turkish counterpart Mevlut Cavusoglu.

Earlier, President Donald Trump said he wanted to reach an agreement with oil company Exxon Mobil or one of the other US companies to exploit oil in Syria. The White House boss earlier this month ordered the withdrawal of all US troops from northeastern Syria, but later declared oil in the country a priority for national security and pledged to send more troops to protect the oil fields.

However, Lavrov said that "any exploitation of natural resources in a sovereign country without their consent is illegal". Zarif added that Iran and Russia are present in Syria at the invitation of the government of the country and "plan to be there as long as the government and the Syrian people want it".

Fahrettin Altun, communications president of Turkish President Recep Tayyip Erdogan, later wrote on Twitter that "Syria's natural resources belong to the Syrians". "Oil or other sources of revenue should be used for efforts to rebuild local infrastructure, supporting people and refugees," Altun said.

US Defense Secretary Mark Esper said this week that the United States would send troops and tanks and armored vehicles to Syria to protect oil fields from self-proclaimed Islamic State militants (IS).

In defense of Trump's decision, US Sen. Lindsey Graham explained that the Syrian oil fields were the main source of income for IS for a long time. "They are now in the hands of the Syrian Democratic Forces (SDF), with the core of the Kurds, having partnerships with the US. So this does not violate any laws," he said.