Elon Musk has taken to social media to lash out at a White House trade adviser . Musk, himself a confidant and adviser to President Donald Trump, called Peter Navarro "dumber than a sack of rocks" and an "idiot" in posts on X.

It is not the first time that the two have clashed. It began after Trump announced last week that the United States would impose import duties of at least 10 percent and higher duties on dozens of countries. The measure is seen as a policy victory for Navarro, who has advocated an aggressive trade policy to stimulate domestic production.

Shortly afterward, Musk called Navarro's Harvard degree "a bad thing" and criticized him for not having built companies of his own. Navarro responded by saying that Musk's criticism was not surprising because the Tesla CEO is not a car manufacturer, but rather a carmaker that sources parts from other countries.

Elon Musk (53) has seen his money go up in smoke, according to Bloomberg news agency calculations. The fortune of the richest person in the world recently fell below 300 billion dollars. Since Trump announced the tariff war, Musk has already lost 35 billion dollars.

The share price of his car company, Tesla, fell. Musk suffered a loss of $4.4 billion on Monday. Since the beginning of this year, Tesla shares have already fallen by 42 percent.