Shares of U.S. rare earth miners rallied in premarket trade on Tuesday, extending sharp gains from the previous session.

President Donald Trump on Friday threatened China with a "massive" increase in tariffs in retaliation for Beijing imposing strict controls on rare earths.

Shares of U.S. rare earth miners rallied in premarket trade on Tuesday, extending sharp gains from the previous session.

As the trade war continues to escalate, China has hit back at Trump by suspending exports of rare earth minerals.