US Secretary of State Michael Pompeo on Thursday said that the Ankara’s purchase of the Russian S-400 air defence system endangers the security of US personnel. Principal Deputy Spokesperson, State Department Cale Brown, said, “Secretary of State Michael R. Pompeo spoke this week with Turkish Foreign Minister Mevlut Cavusoglu to discuss the December 14 imposition of sanctions by the US on our NATO Ally Turkey for its procurement of the Russian-made S-400 missile defence system, as required under the Countering America’s Adversaries Through Sanctions Act. Brown said that Pompeo cleared that Turkey’s purchase of the S-400 system endangers the security of US personnel and military technology and allows Russian access to the Turkish defence industry and armed forces. US Secretary of State Pompeo also urged Turkey to resolve the S-400 issue in a manner “consistent with our decades-long history of defence-sector cooperation” adding that Turkey must recommit itself to its NATO obligations to obligations to purchase NATO-interoperable weaponry. Also Read: Thailand eases corona norms tourists before peak travel Singapore's Changi airport goes sub-zero for Covid-19 vaccine transport plan Pregnant women with COVID-19 do not get sicker: Research