The guard dogs are marking their territory.
For years, the Port Authority and the NYPD have battled over who should provide security at Ground Zero — with each claiming jurisdiction over the hallowed site and trying to squeeze out the other.
The PA Police Department lobbed a salvo at its city-cop rivals last month by putting up a guard booth at the site bearing the agency’s logo.
The move riled NYPD officials, who retaliated Wednesday night by ordering cops to roll up a massive mobile command center, bearing the department’s own giant logo, and park just feet away.
Angry PAPD bosses first tried to use diplomacy — asking the NYPD in the nicest way possible to lose the truck, sources said. But the department refused.
Not to be outdone by the city cops, the PAPD then looked to its own fleet for retaliation. A few hours later, they pulled up behind the NYPD’s truck with a newer, shinier, more high-tech command center that even had a satellite dish on top.
“Our truck came in the morning, and they brought theirs in the afternoon. It’s like, look, ours is bigger and newer than yours,” an NYPD officer told The Post.
A PA insider said the guys in charge felt their territory was being invaded.
“It’s tantamount to the NYPD parking their vehicle in someone else’s driveway,” said the source.
But another law-enforcement source added, “There’s better use of police resources than this childish need to one-up each other.”
The NYPD’s “Communications Division Command Post” truck is used as an office on wheels — with laptops, several TVs, radios and telephones. It handles “communications during major incidents” and costs roughly $500,000, police sources said.
In contrast, the PA’s “Police Mobile Command S.O.D.” costs about $1 million and features a spotlight, sensor cameras, a roll-down awning and is used for special operations.
The truck-measuring contest comes after PA officials announced earlier this year they plan to tear up a four-year-old deal that allows the NYPD to run security at Ground Zero.
The two agencies are also duking it out over who should foot the bill for security at the site.
Both agencies plan to patrol the area when the Freedom Tower opens next year.
Cops near Ground Zero likened the turf war to a playground fight. “We were all laughing about it — but the higher ups aren’t,” an NYPD officer said.
Construction workers near the site got a kick out of the police standoff — and picked a winner.
“For the record, yours is better,” the worker told a PA supervisor.
Additional reporting by Jamie Schram