US President Donald Trump (L) and Turkish President Recep Tayyip Erdogan. (File photo: CGTN)
WASHINGTON, April 29 (Xinhua) -- US President Donald Trump spoke over phone with his Turkish counterpart Recep Tayyip Erdogan on Monday over the issue of Ankara's purchase of S-400 missile defense system, said the White House.
Trump and Erdogan discussed trade, security concerns in northern Syria, and Turkey's planned purchase of the Russian made S-400 system, according to a White House statement.
Turkish Presidency said in a statement the same day that Erdogan had brought forward the proposal to form a working group concerning the procurement of the S-400 systems from Russia during his phone conversation with Trump.
The White House statement, however, made no mention of the Erdogan's working group proposal.
The United States has been in a feud with Turkey over the latter's purchase of Russian S-400 air defense system.
The United States argued that Russian missiles on Turkish territory could gain valuable intelligence on the technical systems of the US-made stealth F-35 jets expected to be delivered to Ankara in November.
During a congressional hearing in March, General Curtis Scaparrotti, head of US European Command, suggested that the United States should cut the sale of F-35 fighters to Turkey if Ankara adopts S-400 system.
On April 3, US Vice President Mike Pence warned Turkey against purchasing the S-400 system from Russia, despite Ankara's firm stance on the deal.
Pentagon announced early this month that it halted "deliveries and activities" related to Turkey's procurement of the F-35 fighter jets program if Ankara insisted on the S-400 deal.
Washington also reportedly threatened to reject sales of Patriot missiles to Turkey in case of the latter's purchase of Russian systems.