The state agency that helps communities pay for school construction and renovations says future projects may need to be scaled back because plunging sales tax revenues could thwart the ability to fund them.

Massachusetts School Building Authority Executive Director Katherine Craven said Wednesday the drop in revenue is "unprecedented."

One cent of every nickel raised by the state’s sales tax goes to the five-year-old agency, which has about $2.5 billion available to spend on projects.

Treasurer Timothy Cahill, who oversees the authority, tells The Boston Globe that projects already approved will be funded, but future projects may need to be scaled back.

The agency is promoting a "model schools" program, which encourages districts to use existing plans. (AP)