Elon Musk lashed out against top White House trade adviser Peter Navarro on Tuesday, calling him "Peter Retarrdo" and "dumber than a sack of bricks," escalating a feud between two of President Trump's allies over the administration's sweeping tariffs.

Musk - who is also a member of the Trump administration - said Navarro was "dumber than a sack of bricks" in posts on his social media platform X. It was in response to an interview Navarro gave in which he criticised Musk.