Turkey will start receiving its order of Russian S-400 air defense systems in July, according to the Turkish president.
"We will hopefully start receiving the S-400 air defense systems which we ordered next month," Recep Tayyip Erdogan told his ruling 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 U.S. and Turkey have escalated in recent months over the S-400 purchase, which Washington said will jeopardize Turkey's role in the F-35 fighter jet program and could trigger sanctions.
Following protracted efforts to purchase an air defense system from the U.S. with no success, Ankara decided in 2017 to purchase the Russian S-400s.
U.S. officials urged Turkey to buy U.S. Patriot missiles, arguing the Russian system would be incompatible with NATO systems and expose the F-35s to possible Russian subterfuge.
Turkey, however, emphasized the S-400 would not be integrated into NATO systems and would not pose a threat to the alliance.
Turkey has urged formation of a commission to clarify any technical issues, but the U.S. has failed to respond to this proposal.