Rep. Mike Turner (R-Ohio) is not backing down from his allegations that President Obama has a “secret deal” with Russia on missile defense.

Turner sent another letter to President Obama on Wednesday that urged the White House to explain what missile defense deals it made with Russia, citing Russian reports that a deal was reached and then dropped without being made public.

Turner and many other Republicans have seized on Obma’s “hot mic” comment to then-Russian President Dmitry Medvedev in March, when he said he would have more “flexibility” after the November election to negotiate on missile defense.