Washington • The Trump administration has decided to pull all U.S. troops out of Syria, a defense official said on Wednesday.

The official, who spoke on the condition of anonymity to discuss a decision that has not yet been announced, said the decision would include the entire force of more than 2,000 U.S. service members. It was made on Tuesday, the official said.

President Donald Trump has long promised to conclude the campaign against the Islamic State and has questioned the value of costly and dangerous military missions overseas.

The decision comes as tensions increase with NATO ally Turkey, which has promised to launch a military offensive against Syrian Kurdish forces, which are partnered with the United States against the Islamic State, in U.S.-controlled territory in Syria.

The withdrawal is expected to occur as quickly as possible, the official said.

The Wall Street Journal first reported on Wednesday that U.S. troops would be withdrawn from northeast Syria.