Subway service across Lower Manhattan resumed just before 1 p.m. Thursday, more than five hours after police abruptly suspended trains throughout the area as the city celebrated the Knicks’ first NBA championship in 53 years.

Police had locked down most of southern Manhattan in the middle of the morning rush hour Thursday as Knicks fans filled parade viewing pens to capacity hours before the event was scheduled to step off at 10 a.m.

The surprise move caught commuters off guard, including those working, studying or going to appointments in the area.

Police said the decision followed massive crowding at the stations that made it physically impossible for people to exit. The NYPD said the situation presented a public safety concern.

While most service had returned by the afternoon, police said there were continuing disruptions on the R & W lines at the City Hall station where the Knicks championship ceremony continued following the parade.

Throughout the morning officers struggled to communicate with each other, and the police and MTA provided contradictory information about service.

Earlier in the day, MTA Spokesperson Aaron Donovan had said trains were still making stops in stations south of Canal, though some were bypassing as many as five stops. MTA bus service was also suspended in much of Lower Manhattan.

“People are getting where they need to go, and stations are open,” Donovan said. “Any time that trains are bypassing any additional stations besides those two, it's at the request of the NYPD, and it's temporary."

But even within the MTA, there seemed to be confusion.

A little after 9 a.m. an empty train rolled through the Bowling Green station to pick up stranded commuters. An MTA employee with a megaphone announced it would be the last train on the 4/5 line to stop at the station until 5 p.m.

At points, PATH trains in New Jersey were dangerously overcrowded and commuters were trying to force themselves into train cars, while hundreds of others were stranded on platforms.

Workers trying to get into their offices also faced confusion. At 111 Broadway, employees had been told to enter through a side entrance. But by 7:30 a.m. the crowd was preventing them from getting anywhere near the police barriers, and officers ignored their pleas for help getting through.

An officer posted nearby told commuters that many people were having trouble getting through the police barriers to go to work and medical appointments. He said communication between officers was difficult because personnel had been brought from all over the city and were on unfamiliar terrain.

Officials with the Department of Education said transportation disruptions in parts of Lower Manhattan had created challenges for some students and staff traveling to school, though schools remained open.

Gloria Chew's sixth grader usually commutes to her school, Lower Manhattan Community Middle School, on her own but on Thursday her mom accompanied her because she knew it would be tricky.

They were heading downtown and couldn’t get off at their usual stop, Bowling Green, because trains were running express to City Hall. They ended up switching lines and crossing a checkpoint to get to the school. The principal, Chew said, had been at the school starting at 6:45 a.m.

“We made it there,” Chew said, but some other families were blocked at checkpoints, gave up, and headed home.

Marilyn Yacobovsky, who lives in the Financial District, said she tried to get her two kids to P.S. 150, which is only a quarter of a mile from where she lives, but they were penned in.

“Parents on WhatsApp were strategizing,” she said.

Yacobovsky tried for 25 minutes “bouncing around,” navigating the barricades but couldn't get through with her children.

Now her kids are home watching the parade and the two parents are working from home. Yacobovsky said it was a little “frustrating” but “everyone's excited.”

“It's all part of the fun of living in New York,” she said. “The school year is almost over. It's one day. It's been 53 years. It's a once-in-a-generation moment.”

Daniel Shapiro, Jessica Gould and Ann Givens contributed reporting.

This is a developing story and has been updated.