Offloading and Threadprivate variables

Is it not possible to offload threadprivate globals?

Compiling the following:

module mymodule   
    integer var_save
    !dir$ attributes offload:mic :: var_save
    !$omp threadprivate(var_save)
end module mymodule

Yields this error:

error #8690: *MIC* A threadprivate variable cannot appear in a DECLARE TARGET directive.   [VAR_SAVE]