McMaster expressed his disapproval of Trump’s course to foreign officials during the lead-up to his trip to Germany. The general specifically said he’d disagreed with Trump’s decision to hold an Oval Office meeting in May with top Russian diplomats and with the president’s general reluctance to speak out against Russian aggression in Europe, according to the three foreign officials.

McMaster and other national security aides also advised the president against holding an official bilateral meeting with Putin.

In a highly unusual move, McMaster did not attend the bilateral meeting with Putin. Only Trump, Secretary of State Rex Tillerson and a translator made up the U.S. side.