WASHINGTON (Reuters) – The top Democrat in the Senate on Tuesday called on President Donald Trump to block Chinese investments in the United States in an effort to pressure China “to help rein in North Korea’s threatening and destabilizing behavior.”

In a letter to Trump, U.S. Senate Democratic leader Chuck Schumer called on the president to use his authority through the Committee on Foreign Investment in the United States, or CFIUS, to exert such economic pressure on Beijing.

Schumer called on Trump to use the inter-agency committee “to suspend the approval of all mergers and acquisitions in the U.S. by Chinese entities.”

“It is my assessment that China will not deter North Korea unless the United States exacts greater economic pressure on China,” Schumer wrote to Trump, a Republican. “The U.S. must send a clear message to China’s government.”

Schumer’s request comes amid increasing U.S. concerns about the threat of North Korea’s nuclear and missile programs. Trump has repeatedly urged China to rein in North Korea.

On Monday, two U.S. officials told Reuters that North Korea’s latest test of an intercontinental ballistic missile has shown that Pyongyang now may be able to reach most of the continental United States.

Led by the U.S. Department of Treasury, CFIUS reviews foreign acquisitions of U.S. companies on national security grounds and can take action on its own or refer cases to the president.

Some Republican lawmakers have called for overhauling the committee to address other concerns about Chinese deals.