A 19-year-old Baruch College student was arrested when he tried to bring a cache of weapons and an M80 firecracker into Trump Tower, a police source said Tuesday.

Alexander Wang, who is from Poughquag but lives in the Baruch dorms, was charged with criminal possession of a weapon and unlawful possession of fireworks, police said. He was awaiting arraignment Tuesday.

Wang allegedly walked up to the bag screening checkpoint on Monday at about 6:30 p.m., police said.

That’s when Secret Service agents found the stash, including a knife with a 6-inch blade, a Swiss army knife, handcuffs, rope, an empty water pistol and an M80 firework.

Wang didn’t have any prior arrest record in the city, police said.

The Secret Service screens all bags that come into the building’s atrium, which is open to the public.