New York (CNN) -- Work on the National September 11 Memorial Museum has been halted over a budgetary dispute, delaying its opening, New York City Mayor Michael Bloomberg said.
"There's no chance of it being open on time. Work has basically stopped," Bloomberg said during a press conference Thursday.
The museum was scheduled to open on the 11th anniversary of the September 11, 2001, terror attacks.
Bloomberg blamed the holdup on "disagreements" with the Port Authority of New York and New Jersey, which is responsible for a portion of the project's financing.
"The Port Authority has to spend money to do the infrastructure that they agreed to," the mayor said. "We have a legitimate claim against the Port Authority for delays for roughly $140 million dollars which has increased our cost."
Bloomberg did not specify when work on the museum halted. The Port Authority did not immediately respond to a request for comment.
Bloomberg's disclosure of the setback came the same day the National September 11 Memorial & Museum Foundation announced that more than a million people have visited the site since it opened on the 10th anniversary of the attacks.
The memorial features two large reflecting pools in the footprints of the two towers.
Located underground in the former World Trade Center's "archaeological heart," the museum will feature 110,000 square feet of exhibition space, according to the website for The National September 11 Memorial & Museum foundation.
It will house a vast array of 9/11 artifacts, including "photographs, videotapes, voice messages, recovered property, clothing and other personal effects, workplace memorabilia, [and] incident-specific documents," among other items.
Bloomberg sounded a note of optimism, telling reporters that both sides would come to "some agreement pretty soon."
He also said he thought the disagreement would not require judges to resolve it. "I don't think it'll get to the court."