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.

Once seen as a modernising force, Dmitry Medvedev has transformed into one of the Kremlin’s most aggressive voices, now at the centre of a rare public clash with Donald Trump.

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.