A young Bangladeshi on a mission to “destroy America” tried to blow up the Federal Reserve Bank in lower Manhattan Wednesday with what he thought was a 1,000-pound van bomb, according to a criminal complaint.

Quazi Mohammad Rezwanul Ahsan Nafis, 21, allegedly wanted to kill scores of people, wreak havoc on the US economy and stop the presidential election when he parked on Liberty Street around 8 a.m. and repeatedly dialed into the cellphone detonator from a nearby hotel room.

But all he did was set off an indicator in the van that proved he tried to set off the explosion. He was promptly arrested, with his grand plans up in smoke.

“I don’t want something that’s like small. I just want something big,” Nafis, 21, told an undercover agent during a recorded August meeting in Central Park.

“Something very big. Very very very very big, that will shake the whole country . . . that will make us one step closer to run the whole world. I want to do something that brothers coming after us can be inspired by us.”

The al Qaeda-obsessed terrorist — who was living with relatives in Queens — also recorded a video addressed to Americans right before he tried to detonate the bomb.

“We will not stop until we attain victory or martyrdom,” he said in the video, in which he covered his face, wore sunglasses and disguised his voice.

Had the bomb been real, the outcome would have been catastrophic.

It “could have done significant damage to the building, possibly taking it down,” said a law-enforcement source.

“It could have killed hundreds of people who were walking by it — and it would have travelled for blocks, taking out windows. Who knows how many people could have been injured from that.”

Looking meek and overwhelmed, Nafis was arraigned yesterday afternoon on charges of attempting to use a weapon of mass destruction and attempting to provide material support to al-Qaeda in Brooklyn federal court.

He was dressed in jeans with the cuffs rolled up, a brown T-shirt and athletic shoes. He sported a trimmed beard.

Nafis, who was held without bail, faces life in prison. He is being held at the Metropolitan Detention Center in Brooklyn.

His attorney, Heidi Cesare, declined to comment.

Federal agents raided his Jamaica apartment, where they took out his computer and boxes of evidence.

Nafis first arrived in the US in January on a student visa, though his sole purpose was to carry out a terror attack, the complaint says.

He attended one semester at Southeast Missouri State University before leaving in May for New York to take ESL classes, sources said.

He was studying cyber-security, a school official said.

While recruiting more terrorists to carry out an attack, he unwittingly enlisted the help of the undercover FBI agent. During a series of recorded meetings, phone calls and Facebook chats, Nafis hashed out his plan and said he had overseas terrorist pals who could help plan an attack.

Nafis first said that considered attacking a US official — which sources said was President Obama — and later named the New York Stock Exchange and a Baltimore military base among possible targets before settling on the Federal Reserve Bank of New York, according to court documents.

The undercover agent introduced Nafis to a colleague who he claimed was an al Qaeda operative. He told that agent he wanted his attack to cause political turmoil. “You know what, this election might even stop,” he told the agent, the complaint said.

During the months he planned the attack, he scouted locations in downtown Manhattan, planning for a possible strike on the stock exchange. He told an agent, “We are going to need a lot of TNT or dynamite.”

He said he needed a “big car with lots of fruits and vegetables in there which can blow up the whole New York Stock Exchange building,” adding that he needed “to make sure that this building is gone.”

He also penned an article he hoped to have published in the al Qaeda magazine Inspire, in which he announced his decision to blow up the Federal Reserve.

He quoted “our beloved Sheikh Osama bin Laden,” to justify the fact that he expected to kill women and children, authorities said.

“All I had in mind are how to destroy America . . . I came up to this conclusion that targeting America’s economy is most efficient way to draw the path of obliteration of America,” he said.

“I decided to attack the Federal Reserve bank of New York which is by far the largest (by assets), most active (by volume) and most influential of the 12 regional Federal Reserve banks.”

Wednesday morning, he and the agent loaded up the van with the fake explosives, which were placed in trash cans and covered with a tarp, before driving to the bank, court papers state.

He also collected the empty explosives bags because he thought they had residue that would create a bigger, deadlier blast.

On the way to the warehouse, he informed the agent that he had a “Plan B” — to set off a suicide bomb if cops tried to stop him, authorities said.

Nafis set up the detonator and attached it to the explosives on the way, the complaint states.

Law-enforcement officials monitored the attempted attack and ensured that the van was not stopped by anti-terror police.

After parking the van, Nafis went to the Millenium Hilton near the World Trade Center, where he and the agent were already checked into a room.

Nafis was surprised when he didn’t hear the explosion, a law-enforcement source said.

“Attempting to destroy a landmark building and kill or maim untold numbers of innocent bystanders is about as serious as the imagination can conjure,” said Mary Galligan, acting assistant director of New York’s FBI field office.

Nafis’ 93rd Avenue neighbors were stunned that the quiet man had attempted mass murder.

However his landlord Rafiqul Islam, 46, said he walked around in religious garb and was “concerned” about Nafis.

“I asked him how long he was going to stay,” he said. “He said he was a guest and will be leaving very soon. It’s very painful and scary. I am living here with my wife and children.”

Additional reporting by Jamie Schram, Lorena Mongelli, Josh Margolin and Helen Freund.

Complaint Against Terror Suspect Nafis