An agreement that paves the way for the completion of the Sept. 11 museum at ground zero has been reached a day before the 11th anniversary of the terror attacks.

The agreement between the Port Authority of New York and New Jersey and the foundation that controls the National September 11 Memorial & Museum was announced Monday. The Port Authority owns the World Trade Center site.

The museum was supposed to open this month, but construction all but ceased a year ago because of a funding squabble between the foundation and the Port Authority.

The underground museum is to house such artifacts as the staircase workers used to escape the attacks.

The memorial includes a plaza where waterfalls fill the fallen towers' footprints. It opened last year and has attracted millions of visitors.

"Today's agreement puts in place a critical and long overdue safeguard to finally protect toll payers and taxpayers from bearing further costs, and, at the same time, put the project on a path for completion," New York Governor Andrew Cuomo said in a statement.

Construction has been halted since last December when a dispute broke out between the museum and the Port Authority, which owns the land.

The Port Authority of NY-NJ, headed by Governors Andrew Cuomo and Chris Christie, said the private foundation running the museum owes hundreds of millions of dollars in construction costs. The foundation, which is chaired by Mayor Michael Bloomberg, disputed the claim.

Some victims' family members were angry that museum would not be ready to open on the anniversary of the attacks Tuesday.

"How long did it take to build Pearl Harbor? How long did it take to do the Vietnam War Memorial?" asked Bill Doyle, whose son, Joseph, died in Tower One. "Why — 10 years, 11 years later — it's still not done?"