Former Russian president Dmitry Medvedev has become embroiled in a tense back-and-forth on social media that prompted U.S. President Donald Trump to announce he had ordered the re-positioning of two U.

“Putin uses Medvedev as a tool to express statements related to nuclear weapons, he doesn’t want to discredit his own good peacekeeper’s name,” Lieutenant-General Ihor Romanenko, former deputy head of the General Staff of the Ukrainian Armed Forces, said ironically.

Dmitry Medvedev has traveled a long way from his time as Russian president, when he once stood beside then-US President Barack Obama and declared that “the solution of many world problems depends on the joint will of the United States and Russia.