CIA Director John Brennan offered a stern parting message for Donald Trump days before the republican U.S. President-elect takes office, cautioning him against loosening sanctions on Russia and warning him to watch what he says.

Brennan rebuked Trump for comparing U.S. Intelligence agencies to Nazi Germany in comments by the outgoing CIA Chief.

The comments reflected the extraordinary friction between the incoming President and the 17 intelligence agencies he will begin to command once he takes office on Friday.

Brennan’s criticism followed a tumultuous week of finger-pointing between trump and intelligence agency leaders over an unsubstantiated report that Russia had collected compromising information about Trump.