Sen. Bernie Sanders on Wednesday condemned as "illegal and unconstitutional" President Donald Trump's newly announced plan to keep U.S. troops in northeastern Syria to control and exploit the region's oil fields.

"Last I checked, Congress never authorized U.S. forces to be deployed to secure Syria's economic resources," Sanders, a 2020 Democratic presidential candidate, tweeted Wednesday.

During a press conference in the Diplomatic Room of the White House Wednesday, Trump said a "small number of U.S. troops will remain in the area where they have the oil." The president did not specify how long or how many U.S. troops would remain stationed in northeastern Syria.

"We've secured the oil," Trump said. "We're going to be protecting it, and we'll be deciding what we're going to do with it in the future."

TRUMP on Syria's oil: "We've secured the oil and, therefore, a small number of US Troops will remain in the area. Where they have the oil. And we're going to be protecting it, and we'll be deciding what we're going to do with it in the future." pic.twitter.com/nKgmXS4yRx — Aaron Rupar (@atrupar) October 23, 2019

The president's remarks came just over two weeks after he abruptly announced the withdrawal of U.S. troops from northeastern Syria, paving the way for Turkey to launch a deadly assault on the region's Kurdish population.

Despite the slaughter, Trump claimed he "saved the lives of many, many Kurds" by negotiating a "ceasefire" in northeastern Syria following the Turkish military operation that he enabled.

"Countless lives are now being saved as a result of our negotiation with Turkey—an outcome reached without spilling one drop of American blood," the president said. "No injuries. Nobody shot, nobody killed."

Dozens of people were reportedly killed during Turkey's bombardment of the Kurds. According to the United Nations, more than 160,000 civilians were displaced by the Turkish invasion.

As Common Dreams reported last week, Amnesty International documented a number of war crimes committed by Turkish forces in northeastern Syria, including indiscriminate bombing of residential areas and "summary killings" of civilians.

"Turkish military forces and their allies have displayed an utterly callous disregard for civilian lives," said Kumi Naidoo, secretary general of Amnesty International.