TORONTO -- Large stretches of downtown Toronto turned into a sea of red and black on Monday as Raptors fans turned out in droves to celebrate the newly crowned NBA champions, the massive crowds raising safety concerns as officials urged supporters to watch the festivities from afar.

Fans dressed in the team's colours packed the parade route while a square outside city hall where the march was to end overflowed with people of all ages. Police worked to stop more supporters from entering the square, which the city said was at capacity.

The masses proved too much for some, who were helped over a barricade by police at Nathan Phillips Square to escape the crush. At one point, officers pulled a semi-conscious child over the barrier and onto a stretcher. Several subway stations near the route were also shut down due to overcrowding.

Nicolas Caramanna, 21, said he'd been in the crowd since 9 a.m. and the gathering soon got rowdy.

"I'm really hot and tired but I'm going to stick around," he said. "When else am I going to get a chance to do this?"

As the parade inched forward -- noticeably behind schedule -- members of the Raptors smiled from open top double-decker buses, some splashing the crowds with champagne. At one point, Kyle Lowry, the longest-serving member of team, was seen hoisting the Larry O'Brien Championship Trophy while some of his teammates smoked cigars.

"This is unbelievable," Lowry said.

Kawhi Leonard, one of the team's star players, also marvelled at the fan response. "Thank you Toronto, thank you Canada for the support, we did it," he said.

Canadian rapper Drake, one the team's most famous supporters, was alongside players, smiling broadly.

Construction workers watched the festivities from scaffolding along the route, and as traffic ground to a standstill on a nearby thoroughfare, some motorists left their vehicles to peer at the activity.

Many fans said they decided not to go to school or work so they could attend the celebration.

"I actually have exams this week but being here is worth it," said 15-year-old Cypher Sabanal, whose mother let him skip school to attend the parade.

John Moreira, meanwhile, had called in sick to work so he could be part of the crowd.

"I told my boss I wanted to be at the parade and he said there wasn't much he could do if I called in sick so that's exactly what I did," said the 31-year-old. "I'm looking forward to seeing the whole team. They all work so hard and deserve all the fans being out here."

For several people, the parade marked a historic moment.

"I haven't seen anything like this happen in the city before so it's great to be a part of it," said 28-year-old RJ Salvador.

Some in the crowd had camped out all weekend in the hopes of nabbing a prime spot along the parade route or at Nathan Phillips Square.

Fans held up signs and enlarged heads of their basketball idols like Leonard and Fred VanVleet. Several hoisted signs urging Leonard, who will become a free agent in the off-season, to stick with the team he helped rise to the top.

As the parade progressed, police took to Twitter asking the public to clear a path.

"Please do not impede the parade route," they wrote. "All viewing areas close to capacity. Be patient and safe."

Viewing screens were set up at Yonge and Dundas square -- north of the parade area -- for overflow crowds to watch the celebrations, with police urging supporters to head there if they felt too crowded. A viewing area was also available at Coronation Park.

Police also said "several children" had been separated from their parents and were being taken to 52 Division where their families could pick them up. GO Transit also set up a designated spot at transit hub Union Station's lost and found for children separated from their group or family.

Some at Nathan Phillips Square appeared to grow impatient, chanting "bring the parade!" Later, several chanted that they wanted water and members of the Raptors dance crew shuttled cups to parched fans pressed against a fence.

Prime Minister Justin Trudeau was scheduled to be among those celebrating, with a brief visit to Toronto planned for later in the day.

Ontario Premier Doug Ford was also expected to watch the festivities from Nathan Phillips Square. His press secretary said Ford wanted the day to be about the fans and players, not politicians.

Mayor John Tory declared Monday "We The North Day" in Toronto, after the NBA champions' slogan. Dressed in his now-famous black-and-gold Raptors blazer, the mayor urged all fans to come celebrate the team's historic win.

Many who couldn't make it downtown watched the festivities from afar. Several schools in the city showed the parade in classrooms and some held their own victory marches for students.

"Today's history lesson in room 137! Watching the GRaptors first victory parade! I told them that one day their children will ask about where they were during the parade and to tell them that the awesome Miss Latchford put the parade on for them in class!," one educational assistant tweeted.

The Raptors' championship win last week came in Game 6 of a rollercoaster Series that captured national attention. On Monday, the Golden State Warriors took out a full-page advertisement in the Toronto Star newspaper, congratulating their rivals for taking the title.

The last time the city held a sports celebration of this magnitude was after the Toronto Blue Jays won the World Series in 1993. That parade saw fans climbing trees and statues on city streets to catch a glimpse of a team that included Joe Carter and Roberto Alomar.