NEW YORK (CBSNewYork/AP) — Some street closures and “no parking” zones are in effect on the Upper West Side as security begins to tighten for Pope Francis’ arrival in New York City on Thursday.

As CBS2’s Hazel Sanchez reported, around-the-clock construction has begun where 80,000 spectators are expected to gather for the pope’s procession in Central Park.

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On Tuesday night, workers were installing specially-made eight-by-eight mesh panels that will make up a massive wall along the park perimeter on Central Park West.

“The mesh itself is non-climbable so no one can try to climb over it,” said John Gerchia of Triton Construction.

Police have also set up security cameras along the route. Tow trucks have hauled away cars on neighboring side streets that are violating the papal parking ban that went into effect Tuesday.

“You can’t be too careful in this day and age, so I think being over-prepared is probably the right way to go,” said Greg Thompson of the Upper West Side.

Indeed, the NYPD is getting ready to carry out one of the biggest security challenges they’ve ever faced. Pope Francis is in town at the same time 170 world leaders are in New York for the United Nations General Assembly.

“It’s a celebratory event for everybody else,” Police Commissioner Bill Bratton said Tuesday on “CBS This Morning.” “For us, this is a security event of the highest level.”

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Police spent Tuesday setting up security cameras along Central Park West as tow trucks made the rounds enforcing the papal parking ban, CBS2’s Janelle Burrell reported.

Cars can no longer be parked along Central Park West and its side streets from the 60s to the 80s to Columbus Avenue, WCBS 880’s Alex Silverman reported.

As part of the security measures, cops have begun lining up 40 miles of steel fencing and 820 tons of concrete barriers, WCBS 880’s Peter Haskell reported. Police have also started setting up a staging area at Columbus Circle.

Mass transit service shutdowns may also take place around papal venues.

In Sunset Park, row after row of police cars could be seen at the Brooklyn Army Terminal, the home base of the massive police operation for the papal visit.

Bratton said the pope will also have “6,000 guardian angels surrounding him.”

“That’s the number of officers we’ll have on duty,” he said. “I’m assuming he’ll bring some of his own, so we can get all the help we can get.”

Even before the pope comes to New York, the NYPD will have a team watching him in Washington D.C.

“What they’re looking for, is effectively, to be there in person so that if there are things to learn from that experience that we want to bring up here,” Bratton said.

In the city, Bratton said the venues are mostly controlled.

“All of our events, as you know here in New York, are ticketed events so we have the ability to screen everybody coming into the physical environment that he’s going to be in,” he said.

Earlier Tuesday, Bratton was the eye in the sky, observing the city from a helicopter, 1010 WINS’ Juliet Papa reported.

“I think we’ve already scared the hell out of everybody to stay away because the traffic is very light around the city,” he said.

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While Bratton said there are no known threats against the pontiff, authorities are closely monitoring activity online.

“What worries us the most is that a lot of this now is Internet driven, in terms of the threat picture, and that means if the conspiracy theory is just between a glowing screen and someone’s mind, it’s very hard to penetrate,” he said.

The NYPD’s Deputy Commissioner of Intelligence and Counterterrorism John Miller said authorities are ready.

“We’ve got layers and layers and layers of different kinds of security on the idea that you have to be, not just on the intelligence side ready to know that you can, but ready to react if you don’t,” Miller said.

Mayor Bill de Blasio said a major collaboration between law enforcement agencies has been months in the making.

“We’re working with the Secret Service, they’re the lead on this,” de Blasio said Monday. “Very, very close cooperation with the Secret Service, the FBI and obviously the NYPD is doing an extraordinary job preparing.”

Starting Thursday, streets surrounding Saint Patrick’s Cathedral will close to traffic from Madison to Sixth Avenue between  48th to 55th streets.

Streets surrounding the residence at 72nd and Madison where Pope Francis will stay will close as well and drivers can expect intermittent closures of the FDR Drive.

On Friday, there will be even more shut downs as the pope travels throughout the city.

He’ll first head to the UN, then to the World Trade Center site, up to Our Lady Queen of Angels School in East Harlem, through the west side of Central Park for a papal motorcade and then down to Madison Square Garden for an evening mass.

“Citizens of New York have been given a great gift — they’ve been told where to avoid,” said Mitch Moss, director of the Rudin Center for Transportation.

De Blasio admitted Monday that the pope’s visit will create inconveniences and traffic delays. The mayor, however, believes it’s worth the inconvenience.

“It’s going to be a joyous week,” he said. “It’s going to be an exciting week. It’s going to be an inspiring week.”

Pope Francis departed Cuba Tuesday afternoon for a roughly three-hour flight to Washington after a four-day trip marked by warm interactions with Cuba’s leaders and subtle critiques of the system they run.

President Barack Obama planned to greet Francis on the tarmac at Andrews Air Force Base upon his arrival from Cuba, according a rare honor to the pontiff.

Once in Washington, Francis will address Congress as part of his itinerary before heading to New York.  Those who have seen his remarks said Francis will speak about climate change and immigration reform during his speech to Congress.

Cardinal Timothy Dolan told “CBS This Morning” that Francis is coming with both a pastoral and political message.

“He’s coming as a pastor,” Dolan said. “Even though he doesn’t come as a politician or as an economist, obviously in the articulation of basic biblical principles — and he’s a pro at that — there’s going to be some implications for the economy, for the environment, for morality, for politics so it’s a little bit of both.”

After his visit to the Big Apple, the pope will travel to Philadelphia.

To see a complete schedule of the pope’s upcoming visit, click here.

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