Boston Mayor Marty Walsh, a labor leader before becoming the city's chief executive, on Wednesday urged Tufts Medical Center officials and the nurses union to return to negotiations as a strike roiled the downtown medical facility.

The nurses strike is Boston's first in nearly three decades.

"This doesn't help anybody," Walsh told reporters at an unrelated event in Boston's Dorchester neighborhood. "This doesn't help anybody. And the hospital will lose money, the nurses are going to lose money, obviously, but most importantly patients are going to lose care. And that's something that shouldn't be happening in our city. We're a world-class medical facility city."

Both sides informed Walsh on Tuesday night that no agreement had been reached and the strike was going forward on Wednesday.

"I certainly don't like seeing a strike," Walsh said this afternoon. "I don't like seeing nurses out on the street today, picketing out on Washington Street, I don't like seeing patients having to go in different doors. But I expect more. Put it that way: I expect more out of both institutions."

The one-day strike, with an additional four days in which the nurses will be locked out, means the two sides won't be talking for five days, according to Walsh. "So you have five days wasted when they could've been negotiating," he said.

His suggestion is that "both sides go in a room, lock themselves in a room for the next 24, 48 hours, don't come out of it and come up with an agreement," the mayor said.

A strike, whether it's short or long, "doesn't help the patients, doesn't help the city, doesn't help the medical industry," Walsh said.

Walsh said there are some similarities between the Tufts tiff and the nurses near-strike he helped avert at Brigham and Women's Hospital officials a year ago. He was asked by the hospital's president and its union to step in and they engaged in "around-the-clock negotiating."

Neither side in the Tufts dispute has asked him to step in but he can, Walsh said. "I'll do it in my office, I'll go to their office."

While he doesn't know all the sticking points in the Tufts strike, Walsh said, "You can always come to an agreement. If you have two sides willing to come to an agreement, you can do that. In this case I'm not sure what the situation is as far as 'willing to come to an agreement.' That bothers me."

A strike, whether it's short or long, "doesn't help the patients, doesn't help the city, doesn't help the medical industry," Walsh said.