FILE PHOTO: A view shows a new S-400 "Triumph" surface-to-air missile system after its deployment at a military base outside the town of Gvardeysk near Kaliningrad, Russia March 11, 2019. REUTERS/Vitaly Nevar

ANKARA (Reuters) - The first shipment of Russian S-400 defense systems to Turkey has been completed and a second shipment is now being planned to arrive in Ankara, Turkish military officials said on Thursday.

Turkey began accepting delivery of the S-400s earlier this month in a move that has strained ties with its NATO ally, the United States.

In response, Washington suspended Ankara from the F-35 jet program over security concerns and has warned of possible U.S. sanctions, but Turkey has so far dismissed the warnings.

On Thursday, the officials said Turkey was still engaged in talks with U.S. officials to procure the Patriot defense system, which Washington had offered as an alternative to the S-400s. They also said France would deploy one SAMP-T battery, a missile defense system developed by the Franco-Italian EUROSAM consortium, along the southern Turkish border.