"We are extremely negative about it. We believe that such ultimatums are inadmissible," Peskov told reporters, when asked about the Kremlin's stand on such statements.
US CNBC broadcaster reported on Tuesday, citing sources, that the United States had given Turkey two weeks to cancel its deal with Russia. Otherwise, Washington will reportedly remove Ankara from the Lockheed Martin's F-35 program.
Washington has threatened Ankara with sanctions for its planned acquisition of S-400s and has repeatedly said it may delay or cancel the process of selling its F-35 aircraft to Turkey. Ankara, in its turn, has said that purchase of military equipment is its sovereign affair and has ruled out the possibility of abandoning its plans.
READ MORE: Turkey RULES OUT Russian-Made S-400 Integration With NATO Infrastructure