A union local representing 5,000 Stop & Shop workers in Connecticut gave notice Wednesday that it could strike as soon as 3 p.m. today, as negotiators for the supermarket chain and the union fell short of an agreement.

Local 371 of the United Food and Commercial Workers Union broke with the four other New England UFCW locals, delivering a mandatory 24-hour advance notice of a possible strike or other job action.

It remained unclear Wednesday night whether Local 371 is planning a strike, or whether — as was suggested on the local's website — the notice was merely a strong-arm tactic heading into today's round of talks in Providence. In any case, the move may signal that either a breakdown or an agreement is near.

"I have informed my membership to stay tuned. There won't be a job action at 3 p.m., but the 3 p.m. deadline going forward gives us the ability to have a job action," said Brian Petronella, president of Local 371, based in Westport.

A Stop & Shop spokeswoman said the company is still negotiating in hopes of a pact, and also is prepared for a strike.

Local 371 represents workers at all 89 Stop & Shop stores in Connecticut — mostly meat, deli and seafood employees. Nearly 10,000 workers at the Connecticut stores are represented by UFCW Local 919 in Farmington, which did not give the notice and instead is awaiting a new offer today from the company.

"He's got to do what he's got to do," said Mark A. Espinosa, president of Local 919, referring to Petronella. "Local 371 — they could go on strike. I'm hoping that won't happen. That would create a little further chaos for us. I'm just hoping, who knows, there may be something given us tomorrow that will satisfy all five local unions."

If Local 371were to begin picketing stores after 3 p.m. today, Espinosa said, he would leave it to individual members to decide whether to remain on the job. "I would encourage them to meet their schedules," he said.

Negotiations between Stop & Shop and the five union locals, which represent 36,000 store employees throughout New England, ended about 6 p.m. Wednesday with union negotiators submitting a counterproposal to Stop & Shop.

Faith Weiner, a spokeswoman for Stop & Shop, said that if the union were to strike, "We could then use temporary replacement workers to run our stores at that time."

Weiner added, "We continue to negotiate in good faith."

The contract expired Feb. 20, but both sides agreed to honor it and keep talking, with an agreement that they give 24 hours' notice before canceling the old contract. All five New England locals voted last month to authorize a strike if talks broke off.

Stop & Shop told its employees on Friday that it offered a $140 million package of wage and benefit increases, worth nearly $3,900 per employee. The company also said it pays workers $1 to $4 an hour more than its non-union competitors.

Petronella said the sides are at odds over wages rather than retirement and health insurance. He said Stop & Shop "keeps coming back with a reconfigured low wage proposal," although neither side has given details of the wage discussions.

In an update posted at 8 p.m. Wednesday on the Local 371website, officials described the 24-hour notification as "an effort to move these negotiations along, and as part of our strategic plan. ... This strategy, as well as others, is meant to compel the company to reframe their final proposals to make them more fair and equitable to all of the members of the New England Locals or face a job action."

Espinosa indicated that the four other locals could join Local 371 in giving notice if talks broke down today.

"I think we're getting close, one way or another. We'll either have a resolution or a strike," he said.

The five union locals have traditionally negotiated and worked together but are free to take independent actions. The last time the UCFW called a strike against Stop & Shop was in 1988, and all five locals participated in the eight-hour walkout, Espinosa said.

"Our goal continues to be the collective voices of Local 371, 328, 919, 1445, & 1459 working together for all of our members," Petronella said in the Web update.

Petronella said he gave the company notice after it provided an unacceptable counter-offer.

"The deadline frees up the ability for our members to do any type of action after 3 p.m. tomorrow," Petronella said Wednesday. "They could picket during their lunch hour, they could picket during their break. I could put up the 12-foot inflatable rat in front of any store I choose."

Stop & Shop employees, of whom about 80 percent are part-time workers, earn from $8.25 an hour, which is minimum wage in Connecticut, to $30 an hour, depending on job classification and length of service, Petronella said.

About 30 percent to 40 percent of the part-time workers are career part-timers with two or more years of service, Petronella said.

Other unions have indicated they would support a strike. On Wednesday, Kurt Westby, Connecticut area director of Local 32BJ of the Service Employees International Union, which represents 4,000 janitors and building service workers in the state, said that union would ask members not to shop at the grocery chain in the event of a strike.