Acting Defense Secretary Patrick Shanahan has said that he expects to solve a dispute with Turkey over its purchase of Russia’s S-400 air defense system. The statement comes a day after the United States halted the delivery of equipment related to the F-35 aircraft to Ankara. “I expect we’ll solve the problem so that they have the right defense equipment in terms of Patriots and F-35s,” Shanahan told reporters at the Pentagon on Tuesday. Washington has sought to persuade Turkey to purchase the Patriot defense system, instead of S-400s. Shanahan also said that he expected the delivery of F-35s currently at Luke Air Force base to Turkey, Reuters reports.