President Recep Tayyip Erdogan said the S-400 issue is directly related to Turkey's sovereignty rights and Ankara "will not take a step back from this."
Turkey will start receiving its order of Russian S-400 air defence systems in July, according to President Recep Tayyip Erdogan.
"We will hopefully start receiving the S-400 air defence systems, which we ordered, next month," Erdogan told the governing Justice and Development (AK) Party's parliamentary group.
Erdogan said the S-400 issue is directly related to Turkey's sovereignty rights.
"We will not take a step back from this," he added.
Tensions between the US and Turkey have escalated in recent months over the S-400 purchase. Washington said the Russia-made defence system will jeopardise Turkey's role in the F-35 fighter jet programme and could trigger sanctions.
Following protracted efforts to purchase an air defence system from the US with no success, Ankara decided in 2017 to purchase the Russian S-400s.
US officials are now urging Turkey to buy US Patriot missiles, arguing the Russian system would be incompatible with NATO systems and expose the F-35s to possible Russian subterfuge.
Turkey, however, emphasised the S-400 would not be integrated into NATO systems and would not pose a threat to the alliance.
Turkey has urged the formation of a commission to clarify any technical issues, but the US has failed to respond to this proposal.