Turkish President Tayyip Erdogan addresses his supporters during a rally for the upcoming local elections, in Istanbul, Turkey March 12, 2019. REUTERS/Murad Sezer

ISTANBUL (Reuters) - It is not possible for Turkey to back out of a deal with Russia to buy S-400 missile defense systems, President Tayyip Erdogan said on Thursday.

He made the comment in an interview with private broadcaster Haberturk. Asked whether it is possible for Turkey to buy the S-400s but not activate them, Erdogan said that was not possible.

Washington has warned that procuring the S-400 systems from Russia could jeopardize defense industry deals between the NATO allies.