US President Donald Trump vowed Tuesday to purchase a Tesla (TSLA) to defy what he described as an illegal boycott of the electric vehicle maker meant to harm its chief executive, Elon Musk, a political ally and member of his administration.

"The Radical Left Lunatics, as they often do, are trying to illegally and collusively boycott Tesla, one of the World's great automakers, and Elon's 'baby' in order to attack and do harm to Elon, and everything he stands for," Trump wrote in a post to his social media platform, Truth Social. "I'm going to buy a brand new Tesla tomorrow morning as a show of confidence and support for Elon Musk, a truly great American."

Trump has previously spoken out against electric vehicles and in favor of internal combustion-driven automobiles.

Tesla shares were up 1.7% in recent premarket activity.