The Catholic Diocese of Arlington is throwing a wrench in Alexandria's plans to build a big new affordable housing complex.

Bishop Michael Burbidge, who leads the Diocese of Arlington, filed a lawsuit April 8 alleging that the diocese has a right to an alley connected with the proposed project at West Glebe Road and Mount Vernon Avenue above the general public, The Washington Post reported.

The church alleges that right has been improperly vacated to make way for the two-building development.

Alexandria Housing Development Corp. is planning the project, which would reserve a quarter of its units for those making 40% or less of area median income and half for those making 60% or less of AMI.

The project has expanded in scope since it was first proposed. After receiving a $500K pre-development loan from the city last year, the developers added an extra 100 units to the residential mix, which includes one- to three-bedroom apartments.

Nearly 40K SF of commercial space is also planned for the site, which would replace two parking lots and a shopping center, according to Alexandria Living magazine.

The diocese operates a school and 72-year-old church building adjacent to the proposed project. Billy Atwell, a spokesman for the Arlington Diocese, told the Post in a statement that the church took "certain steps under the law ... to protect its property rights now and into the future."

“The current plans negatively impact the ability of the parish and the school to serve its members and the local community and diminishes its legal rights and property interests,” Atwell told the Post.

Some community members associated with Saint Rita spoke against the project during public meetings, according to the Post, but it was approved unanimously by Alexandria City Council members.

It remains unclear how long the lawsuit could halt the project, and the city said it had not yet been served. If the development proceeds, it would join a pipeline of affordable, dense projects that Alexandria hopes will help reverse a long-term decline in workforce housing.