Turkey has continued receiving components of a Russian-made air defence system for a second day, despite Washington's warnings that it will impose sanctions on the NATO-member country.
Turkey's defence ministry tweeted Saturday the landing of a fourth Russian cargo plane in Murted Air Base, near the capital, Ankara.
On Friday, the ministry announced the much-awaited delivery of S-400 components had begun.
The United States has repeatedly warned it will impose economic sanctions and kick Turkey out of the F-35 stealth fighter jet program if Ankara does not drop its S-400 purchase. Turkey has refused to bow to U.S. Pressure, saying its defence purchase is a matter of national sovereignty.
The U.S. Administration was publicly silent Friday on how it would respond to the delivery.