Five-year-old negotiations between Harvard and Cambridge over the University’s planned government center came to a screeching halt this week—and as a midsummer deadline quickly approaches, neither side has a plan.

Harvard representatives said last night they are willing to scrap what they have often described as the project’s “centerpiece”—a tunnel to connect the two buildings, which is the only piece lacking official permission—in order to leave the negotiations behind and begin construction on the Center for Government and International Studies (CGIS).

“We are prepared to build the buildings without the tunnel,” University Director of Community Relations Mary H. Power told the Mid-Cambridge Neighborhood Association (MCNA) in an unprecedented statement last night.

Officials have said that in order to keep construction plans on track, they need to know if they have permission for the CGIS tunnel—which only the Cambridge City Council can grant, because it would cut beneath a city street—by this summer at the latest.

And since the city council has only one summer meeting, on July 29, that leaves Harvard and the neighborhood a mere two weeks to hammer out a deal.

Some said they regarded Power’s remark as a negotiating “ploy,” since Harvard has focused for months on getting permission for the passageway. Also, in an agreement that was recently abandoned, Harvard offered millions of dollars worth of benefits to the neighborhood in exchange for the tunnel.

But if Power’s statement was a ploy, no one from the community bit last night. With applause and nods, the group agreed once again last night on an informal motion that they oppose the tunnel, which residents have said would bring months of disruptive construction and traffic problems to Mid-Cambridge.

Over the past five years, Harvard and the neighbors—who have often said they feel the project represents institutional encroachment into their neighborhood—have met, discussed and revised the CGIS plans, and five city boards have signed off on the project.

But for the past seven months, the lone problem has been the tunnel, which planners have described as crucial to CGIS—but it has also become the project’s Achilles’ heel, as obtaining the easement for the tunnel requires permission from two-thirds of the Cambridge city council.

Councillors have often and loudly stated that they do not want to support the tunnel until they see a public benefit for Mid-Cambridge, the neighborhood in which Harvard plans to locate the CGIS.

In April, when the tunnel first came up for city council vote, the councillors postponed making a decision and instead created a negotiating team of representatives from Harvard, the city and Mid-Cambridge, expressing the hope that a mutually beneficial settlement could be reached.

And according to the city manager’s initial letter about the group, their work was supposed to be complete on May 29.

After approximately a dozen meetings, the team came up with a tentative agreement, including millions of dollars worth of concessions from Harvard.

Under the agreement, the University promised to donate a parcel of land at 18 Sumner Rd. for a neighborhood park. Harvard also promised to forbid the use of CGIS for summer school and extension school classes for five years, and agreed to a decade-long moratorium on future construction for the Foxcroft-Bromley Court block, as well as five-year moratoria on the Gund Hall and Sackler Museum blocks.

Two of the four community negotiators initially signed onto the agreement on July 3.