The United States has urged Turkey to exercise restraint and avoid civilian casualties in its cross-border operation against Kurdish militants in Syria.

In a statement, State Department spokeswoman Heather Nauert said we urge Turkey to ensure that its military operations remain limited in scope and duration.

It is pertinent to mention here that Turkey has launched an operation "Olive Branch" seeking to oust from the Afrin region of northern Syria the 

Meanwhile, US Defense Secretary Jim Mattis Ankara says Turkey has legitimate security concerns in the area along its border with Syria.

Talking to reporters aboard his aircraft at the start of a trip to Asia, he said Turkey had given Washington advance warning before launching an operation against Kurdish militants in Syria.

It is pertinent to mention here that Turkish troops and allied Syrian rebels have launched an operation against the Kurdish militants in Syria's Afrin town. AFP