U.S. President Barack Obama did not put money in his federal budget proposal for a customs plaza on the Detroit side of a planned bridge between the city and Canada.

Obama sent his $3.9 trillion fiscal 2015 budget to Congress on Tuesday, but it doesn't include the $250 million cost of a border inspection plaza.

The plaza is a vital part of the planned New International Trade Crossing to link Detroit to Windsor, Ont.

The Canadian government is funding most of the bridge, expected to open in 2020.

Democratic U.S. Rep. Gary Peters calls the decision not to fund the plaza a "grave mistake."

New International Trade Crossing coalition spokesman Tom Shields says the full $250 million isn't needed in one year but can be spread over several years.

Roy Norton, Canada's consul general in Detroit, said “all of the other hurdles have been overcome” in moving forward with a new bridge.

Last year, Obama issued a presidential permit for the bridge. Only America's commitment to a new customs plaza is lacking.

“There’s no formal commitment on the part of the U.S. government to fund that customs plaza,” Norton said.

In February, two senators and five members of U.S. Congress sent President Obama a joint letter asking for his support of the project.

“We are writing to urge your prompt attention to an important infrastructure project proposed to be constructed along the northern border, a project vital to our nation’s security and economic future which will create thousands of jobs in Michigan,” the letter reads, in part. “Given the importance of this project to international trade and to the economy of Michigan, it is our hope that the groups involved can come together to resolve the funding concerns about the U.S. Federal Plaza.”

With files from CBC News