The Trump administration announced on Wednesday that it would withhold $18 billion in federal infrastructure funds previously awarded to New York City, including funding for two major transportation projects.

In a statement, Sean Duffy, the transportation secretary, specifically mentioned the expansion of the Second Avenue subway line and the construction of new train tunnels under the Hudson River, a $16 billion project known as Gateway.

He said that funds for those two projects would not be distributed while the Transportation Department reviewed what it described as New York State’s “discriminatory, unconstitutional contracting processes.”

The review was in response to President Trump’s executive orders earlier this year targeting diversity, equity and inclusion programs, Mr. Duffy said.

“The department is focusing on these projects because they are arguably the largest infrastructure initiatives in the Western Hemisphere,” he said in a statement.

It was not immediately clear whether the $18 billion involved just those two projects or others as well.

Former President Joseph R. Biden Jr.’s administration awarded the Metropolitan Transportation Authority $3.4 billion in federal funding in 2023 to extend the Q line on Second Avenue from the Upper East Side into Harlem and East Harlem, an expansion of a project that has been in the works for more than a century.

The following year, the Biden administration awarded $11 billion in grants and financing for the Gateway Project.

The Gateway Development Commission, which oversees the Hudson tunnel project, held its monthly board meeting on Tuesday. No mention was made of a possible suspension of funding.

This is a developing story. Check back for updates.

Stefanos Chen and Patrick McGeehan contributed reporting.