President Donald Trump signed an executive order on Tuesday that launched a national security investigation into the U.S. reliance on imports of critical minerals, after China suspended exports of certain rare earth metals and magnets.

In a Tuesday social media post, President Donald Trump claimed he will protect farmers and said he recognizes he had to support them financially during his first administration after they were hit by a trade war with China.

The Trump administration plans to isolate China through a tariff pressure campaign against over 70 U.S. trade partners, the Wall Street Journal reports.