By
Turkey shelled targets in northern Syria on Monday and said it would swiftly crush the US-backed Kurdish YPG fighters who control the Afrin region, amid growing international concern over its three-day-old military operation.
"We are concerned about the Turkish incident in Northern Syria," Tillerson said while on a trip to London, according to a pool report supplied to Reuters.
"We recognize and fully appreciate Turkey's legitimate right to protect its own citizens from terrorist elements," he said.
Tillerson said he is asking that both sides show restraint and minimize civilian casualties, and that the US is aiming to "see what we can do to work together to address turkey's legitimate security concerns."