New Delhi, April 8 -- Elon Musk on Tuesday described Peter Navarro, a senior White House trade advisor, as "truly a moron" and "dumber than a sack of bricks" in a growing rift over Donald Trump's tariff policy.

Musk, a key aide to the president, has signaled opposition to the tariffs, and the Tesla CEO hit out after Navarro described him as "not a car manufacturer" but "a car assembler."

Peter Navarro, President Donald Trump's top trade adviser, on Monday dismissed tech-billionaire Elon Musk's push for "zero tariffs" between the United States and Europe, calling the Tesla CEO a "car assembler" reliant on parts from other countries.

Navarro, widely seen as the architect of Trump's tariff plans, told CNBC Musk had done a good job with hi...