WASHINGTON (AP) — The Senate’s top Democrat is calling on the federal government to step in and investigate whether a plan for new subway cars in New York City designed by a Chinese state-owned company could pose a threat to national security.

Sen. Charles Schumer of New York said in a statement to The Associated Press on Sunday that he’s asked the Commerce Department to conduct a “top-to-bottom review” after CRRC, one of the world’s largest train makers, won a design contest for new subway cars that would include “modern train control technology.”

The company hasn’t won a contract in New York City, which has America’s biggest transit system, but it has been awarded contracts in recent years for new subway cars in Los Angeles, Chicago, Boston and Philadelphia.

In announcing the contest winners last year, the Metropolitan Transportation Authority, which operates the subway system, said CRRC had proposed investing $50 million of its own money to develop the new subway cars. The contest was designed to bring out new ideas for future projects but did not lead to any contracts for new subway cars and the MTA is not currently purchasing any new cars.

But in the last few years, China has pushed to dominate the U.S. rail car market, a multibillion-dollar industry. CRRC is also believed to be pursuing a $500 million contract with the Washington Metropolitan Area Transit Authority in Washington, D.C.

Security experts and members of Congress have raised the alarm about CRRC because it is owned by the Chinese government, warning of prior cyberthreats and hacking attacks linked to Chinese intelligence officials. They fear allowing the company to install technology in America’s rail system could potentially expose it to cyberespionage and sabotage.

Schumer’s call for an investigation comes amid rising tensions between the U.S. and China after trade talks between the two nations broke up earlier this month without an agreement. Days ago, President Donald Trump signed an executive order to declare a national economic emergency that empowered the government to ban American telecommunication companies from installing foreign-made equipment and technology that could pose a threat to national security.

“The MTA has robust, multilayered and vigorously enforced safety and security standards, but we support efforts of government agencies to bolster that work,” spokesman Max Young said.