The US Treasury Department on Monday imposed sanctions on Turkey over its purchase of the Russian S-400 missile defense system.
The sanctions, which are part of Countering America's Adversaries Through Sanctions Act (CAATSA), targeted Turkey's Presidency of Defense Industries (SSB), its head Ismail Demir and three other officials.
US State Secretary Mike Pompeo said in a statement SSB knowingly engaged in a significant transaction with Rosoboronexport, Russia's main arms export entity, by procuring the S-400 surface-to-air missile system.
"The sanctions include a ban on all US export licenses and authorizations to SSB and an asset freeze and visa restrictions on Dr. Ismail Demir, SSB's president, and other SSB officers," he added.
President Donald Trump said in June 2019 that former President Barack Obama administration had treated Turkey unfairly when Ankara requested to purchase US defense systems.
"Obama administration said no, no, no to Turkey when they wanted to purchase Patriots and they [Turkey] bought S400," Trump said during his closing speech at the G20 summit in Osaka, Japan.
Pompeo urged Ankara to resolve the S-400 problem immediately in coordination with Washington.
"Turkey is a valued ally and an important regional security partner for the United States, and we seek to continue our decades-long history of productive defense-sector cooperation by removing the obstacle of Turkey's S-400 possession as soon as possible," he said.