The city Transportation Department on Tuesday dispatched trucks with flashing electronic billboards around Times Square to warn tourists and others that they can’t carry a gun in the area without soon facing arrest.

Two white DOT pickup trucks towed the electronic signs around the Crossroads of the World ahead of a new law that bans even legal concealed firearms from such designated “sensitive areas” starting Thursday, 1010 WINS radio reported.

“TIMES SQUARE — GUN FREE ZONE — LICENSED GUN CARRIERS AND OTHERS — MAY NOT ENTER WITH A GUN UNLESS OTHERWISE — SPECIALLY AUTHORIZED BY LAW VIOLATION — OF THIS PROHIBITION IS A FELONY,” the messages said, according to a video clip posted on Twitter.

The city’s subways and buses, schools, libraries, airports, bars and entertainment venues are also among the “sensitive locations” specified in the law that Gov. Kathy Hochul signed on July 1.

The move came in response to a landmark decision by the US Supreme Court that will ease the way for people to obtain licenses to carry handguns across the state.

The high court’s 6-3 ruling struck down a 1913 law, known as the Sullivan Act, that required applicants for pistol permits to show “proper cause” as to why they needed to pack heat in public.

The City Council’s Public Safety Committee was holding a hearing Tuesday on a bill to define the boundaries of Times Square and to authorize the NYPD to adopt rules so people with so-called carry permits who live or work there can still enter the area with their weapons.

The committee’s proposal would set boundaries that “largely follow the area identified as Times Square by the official NYC Tourism website and City’s Times Square Business Improvement District.”

The area would be “bounded by West 40th Street to West 53rd Street and Sixth Avenue to Eighth Avenue and part of Ninth Avenue and the Port Authority Bus Terminal,” according to the resolution.

In its June 23 majority decision, the Supreme Court said it was “settled” that weapons could be banned “consistent with the Second Amendment” from places including legislative assemblies, polling places and courthouses.

“And courts can use analogies to those historical regulations of ‘sensitive places’ to determine that modern regulations prohibiting the carry of firearms in new and analogous sensitive places are constitutionally permissible,” the ruling said.

The New York City bill’s sponsor, Council Speaker Adrienne Adams (D-Queens), has said the Supreme Court’s overall ruling posed a “very serious” threat to the Big Apple and at one point called on state lawmakers to designate virtually the entire city a “sensitive location.”

Adams, who has apparently given up on that request, noted the DOT’s mobile billboards during Tuesday’s hearing.

“I’d like to see these signs in a lot more areas around the city of New York,” she said.

NYPD lawyer Robert Barrows testified that the department wasn’t planning to flood Times Square with additional cops to enforce the new law.

But Barrows, the NYPD’s executive director of legal operations and projects, said new training would help officers spot people carrying weapons.

Barrows also said the NYPD is using social media to try to identify people who might try to bring guns into Times Square and other prohibited sites.