U.S. President Joe Biden plans to express concern over Nippon Steel's proposed $14.9 billion purchase of U.S. Steel, a person familiar with the matter said Wednesday, pushing the U.S. company's stock nearly 13% lower on bets the deal could face greater political opposition.

The issue has the potential to overshadow an April 10 summit between Biden and Prime Minister Fumio Kishida aimed at boosting the long-standing security alliance between their countries in the face of growing Chinese strength.

In December, Nippon Steel clinched a deal to buy the iconic, 122-year-old U.S. steelmaker for a hefty premium, betting that U.S. Steel would benefit from the spending and tax incentives in Biden's infrastructure bill.