-- Hours before they planned to picket city-sponsored welcome parties on the eve of the Democratic National Convention, Boston firefighters agreed to contract terms with the city, ending a fractious, months-long labor dispute that disrupted preparations for the event.

Members of Firefighters Local 718, who had been working without a contract for two years, will get a 10.5 percent raise over the next three years. Along with Boston police, who received a contract through arbitration last week, they agreed to call off pickets planned for Sunday night.

"We have labor peace in Boston at this hour," Mayor Thomas M. Menino told reporters Sunday morning after a marathon negotiating session. "There's a climax to every story. This was the time to end this chapter.''

The news came as delegations from across the country, several of whom had said they would not cross union picket lines at convention events, arrived for the first night of convention hobnobbing, including a concert by the Boston Pops on City Hall Plaza.

About 3,000 antiwar demonstrators gathered on Boston Common before the festivities began, many carrying bullhorns and banners, and paraded past the convention site in the week's first large-scale protest.

Under a bright blue sky, a host of speakers addressed what started as a sparse crowd from a makeshift stage. Brian Becker, a member of the steering committee of Act Now to Stop War and End Racism, which calls Republicans and Democrats "the twin parties of the war machine," implored the crowd to "stand with the people of the world, which means stand against Bush and stand against the Democrats."

Becker's group led the event, but participants included opponents of a proposed constitutional amendment banning gay marriage, a group calling for the release of jailed people it deemed political prisoners and a man passing out leaflets that asked people not to vote.

Some attendees said that the turnout was underwhelming because activist groups were husbanding their resources for next month's Republican National Convention in New York, where demonstrations are predicted to be many times as large.

"What you've got here is more of the hard-core, full-time activists, as opposed to the rank and file," said Bill Strubbe, 49, of Oakland, Calif., who was selling inflatable dolls of President Bush with a long nose like Pinocchio. "A lot more are going to come out of the woodwork in New York, a half-million at least."

Walter Daum, editor of Proletarian Revolution magazine, said, "We mobilized everyone for whom it would be convenient to come, but for the Republicans, we're mobilizing everybody."

Chanting, "From Iraq to Palestine, occupation is a crime!" the group marched past the Beacon Hill statehouse and down to Causeway Street, which passes FleetCenter, the convention site. Boston police denied organizers a permit to use that route for the parade, but a federal judge overruled the decision last week.

On the return leg, they walked past a group of antiabortion demonstrators lying in the street inside chalk outlines. Brandi Swindell, of the group Generation Life, said the display was intended to symbolize "the lives ended each year by abortion."

Boston Police Superintendent Bobbie Johnson, who walked in front of the paraders and coordinated a large and visible contingent of officers, called the event "very peaceful, just as we expected."

Peace in the city's protracted standoff with its unions, however, had looked unlikely as recently as a few days ago, when the Boston Police Patrolmen's Association (BPPA) said that despite a 14.5 percent raise it would lead pickets at Menino's public appearances unless other unions' deals were finalized. On Friday, City Hall reached agreements with three other police unions and the agreement with the firefighters was finalized Sunday morning.

Jim Barry, a BPPA spokesman, said members had been called Sunday afternoon and told that the demonstration was off.

But some disruptions were not reversible. The Boston 2004 host committee canceled welcome parties at the request of the Michigan and Ohio delegations last week when it appeared the dispute might not be resolved.

Isiah Leggett, chairman of the Maryland Democratic Party, said Sunday that his delegates would not attend the city's welcome party and would instead gather at Boston's World Trade Center for a reception sponsored by Dominion Power.

"We made a decision based on facts we had at the time," he said. "We decided rather than deal with the confusion we'll just skip it altogether."

Staff writer Tim Craig contributed to this report.

Pedestrians walk past members of a large and visible police contingent lined up near FleetCenter, the site of the Democratic National Convention. Antiabortion protesters lie inside chalk outlines on a Boston street as antiwar protesters walk by during their march toward FleetCenter. Labor disputes had disrupted convention preparations.