Mayors, police officers and crime watch organizers from 13 Boston-area communities gathered on the Mass. Ave. Bridge Tuesday morning in a display of unity and a celebration of National Night Out.

As part of the day-long activities centered around community participation in crime fighting, city officials and volunteers joined hands above the Charles River as a boat from the fire department sprayed fountains of water into the air in the background.

Christopher F. Hayes, director of the Neighborhood Crime Watch unit for the Boston Police Department, who opened the speech-making portion of the event, said the day was important for many reasons.

"This is a day of celebration, self-congratulation and recommitment," Hayes said. "Working together we will continue to make progress. Our streets and our neighborhoods belong to us."

Boston Mayor Thomas M. Menino said the celebration of National Night Out was sending a message to felons.

"We are telling the criminal element in our community there's no boundaries in fighting crime in the greater Boston area," Menino said

Cambridge Mayor Sheila T. Doyle Russell also spoke, presenting a proclamation of thanks and congratulations.

James A. Sheets, mayor of Quincy, said the celebration showed the Boston area's resolve against crime.

"We're here because crime knows no boundaries," Sheets said. "We're committed; we're here because we believe."

Paul F. Evans, police commissioner of the City of Boston, emphasized the need for cooperation between the government and the community.

"What we're celebrating is the relationship between police, the neighborhoods, and the people we serve," Evans said. "We can't do it alone. We have to work with the community."

After the round of short speeches, the ceremony was concluded and the officials mingled with community organizers and press, expressing their satisfaction with the event.

"It's wonderful," Russell said. "It's bigger than ever this year."

Menino also praised the occasion.

"The event is very significant in that 13 communities have come together to send a message: there are no boundaries, there are no walls," he said. "We're all together fighting crime."