Trump and Erdogan hold phone conversations

US President Donald Trump and Turkey's president, Reccep Tayip Erdogan, during a telephone conversation discussed the Turkish proposal that through a joint task force address disagreements over Ankara's plans to purchase a Russian-400 missile defence system, the Turkish presidency announced.

The president raised the proposal for the creation of a working group related to the S-400x1 defence system, the report said.

The two countries have been opposing each other for months over opportunities for Turkish military equipment with the Russian system.

The United States says this system is not in line with NATO's defence network and can compromise its F-35 aircraft.

Ankara has said a working group could assess the impact of the Russian S-400 system on fighter aircraft. US Secretary of State Mike Pompeo and several US senators have warned Turkey that it will be punished for buying S-400, under a law requiring sanctions against countries receiving military equipment from Russia.

Turkey has said that as a NATO member, it poses no threat to the United States, and sanctions should not be implemented against it.

The White House confirmed on Monday that Trump and Erdogan had discussed the planned purchase of Turkey's planned Russian missile defence system S-400.

Trump and Erdogan also discussed trade between the two countries and the crisis in Syria, the White House said.