With an eleventh-hour agreement Sunday night to extend bargaining on a new contract for Westport school bus drivers -- avoiding a strike Monday morning -- officials hope to resolve the impasse during a "cooling off" period.

The drivers represented by United Food and Commercial Workers, Local 317, had voted earlier Sunday to reject the latest contract offer from Dattco bus company and to walk off the job at the start of classes early Monday.

But at the request of the Federal Mediation Conciliation Service, both sides agreed to continue talks later this week and the strike was called off -- at least as of Monday. A federal mediator will try to help forge an agreement when talks resume.

"There are major issues that we're trying to work out, and there's some really good hard work being done, and we're happy to still be at the table," said Cliff Gibson, the bus company's chief operating officer. "We're glad that the union feels the same way, and we appreciate the services of the federal mediator at this point."

Gibson did not disclose Dattco's proposed contract terms for the drivers. The negotiations between bus contractor and the union pertain to benefits and pay, but Gibson declined to specify the issues of contention between the two sides.

The cooling off period does not have a designated duration, nor do Dattco and union leaders have to reach a contractual settlement by a certain deadline, Gibson added. While the two sides continue to negotiate, the drivers will work under the terms of their former contract, which expired at midnight Monday.

"I'm very confident that the management of Dattco and the union are honestly looking for a solution to the crisis," said Superintendent of Schools Elliott Landon. "I'm very hopeful that there will not be a strike."

New contract terms for the drivers will not affect the cost of the school district's current five-year contract with Dattco, which runs until June 2014.

"I anticipate that the contract will continue to be honored as is," Landon said.

Phone messages left for Thomas Wilkinson, president of Local 317, were not returned.

Cancellation of the strike capped a frenetic weekend of negotiations between bus company and union representatives.

In an email to parents earlier Sunday, school officials had said that about 75 Dattco school bus drivers, represented by the UFCW, had rejected a proposed settlement with management and would walk off the job Monday morning.

The town's school system late Thursday had begun warning parents of the possibility that there would be no buses.

"We have done our part to meet regularly with union officials to resolve contract issues, and we will continue to meet over the weekend to keep our drivers -- whom we highly respect -- behind the wheel," Gibson said in a statement issued before the drivers voted to strike.

In an email to parents of Westport students, Landon had warned that "there will not be bus service to transport your children to and from school beginning Monday morning" if a new contract agreement were not reached between the school system's transportation provider and its drivers by 12:01 a.m. Monday.

"I urge you to make every effort to have your children arrive at school approximately 30 minutes prior to their normal school start times," Landon said in the email last week.

The superintendent had suggested car pools be organized as a transit option if the strike went forward.

He said extra police would have been assigned to direct traffic anticipated at the schools.