WASHINGTON — More than 100 current and former top executives at major U.S. companies are calling on Congress to pass long-term relief to ensure that small businesses survive the coronavirus pandemic.

In a letter to top congressional leaders of both parties in the House and the Senate that was released Monday, the CEOs and other executives warn of significant consequences to the economy if Congress doesn’t immediately act to save small business.

“By Labor Day, we foresee a wave of permanent closures if the right steps are not taken soon,” they wrote. “Allowing small businesses to fail will turn temporary job losses into permanent ones. By year end, the domino effect of lost jobs — as well as the lost services and lost products that small businesses provide — could be catastrophic.”

The letter, spearheaded by Howard Schultz, chairman emeritus of Starbucks, was also signed by Facebook Chief Operations Officer Sheryl Sandberg, Microsoft CEO Satya Nadella, Walmart CEO Doug McMillon and U.S. Chamber of Commerce CEO Thomas Donahue, among many others.

In addition to pushing for another round of short-term relief through the Paycheck Protection Program, they called on lawmakers to pass legislation similar to a measure proposed by Sens. Michael Bennet, D-Colo., and Todd Young, R-Ind. Their bill would extend the period for the hardest-hit businesses whose revenues have declined by at least 25 percent to use their paycheck protection funds and meet requirements for loan forgiveness.

Specifically, the company executives said in the letter that the legislation should include federally guaranteed loans “that will enable small businesses to transform and sustain themselves through 2020 and well into 2021.” They said the support “must last for longer than just the next two or three months.”

Congress is struggling to negotiate another comprehensive coronavirus relief package.