Turkey created a "very terrible" situation in Syria, Pentagon chief says

• Esper says there was not a possibility that U.S. was going to start a war with a NATO ally.
• Critics say U.S. President Donald Trump's decision enabled the Turkish offensive.
• The American pullout from northeastern Syria has raised concern that it could allow a resurgence of Islamic State militants.

Last week, Esper said he would press NATO allies "to take collective and individual diplomatic and economic measures in response" to Turkey's incursion into northeastern Syria, even as critics have pointed out that U.S. President Donald Trump's decision enabled the Turkish offensive.

Earlier this month, Trump announced that the United States would be withdrawing it's troops from northeastern Syria, clearing the way for Turkish troops to launch an offensive against Kurdish fighters in the area.

"There was not a possibility that we were going to start a war with a NATO ally," Esper said.

Speaking at an event organised in Brussels by the German Marshall Fund think tank, the Defense Secretary urged Ankara to demonstrate that it was still a "responsible" NATO ally.

The American pullout from northeastern Syria has raised concern that it could allow a resurgence of Islamic State militants.

Esper said he already talked to his British and French counterparts and that the U.S. was still committed to continue the fight against Islamic State militants. He was expected to discuss the topic further at a meeting of NATO defence ministers later in the day.