The renewed U.S.-China trade truce struck in London left a key area of export restrictions tied to national security untouched, an unresolved conflict that threatens a more comprehensive deal, two people briefed on detailed outcomes of the talks told Reuters.

Investor interest in rare-earth minerals is rising, a source of strength for shares in the rare-earth miner MP Materials. The stock rose Friday after jumping late Thursday following a Bloomberg report that the Defense Department might provide additional capital to boost production.

The U.S. trade "deal" with China highlights how dependent Americans are on Chinese rare earth minerals, creating an economic vulnerability.