His bag snagged on a fence and pulled him under the truck's rear wheels, police said. View Full Caption DNAinfo/Amy Langfield

MIDTOWN — A man was crushed to death when he chased down and hopped onto a passing dump truck before getting pulled under its rear wheel Monday night, police said.

The man, 29, whose name wasn't immediately released, was standing at the intersection of West 51st Street and Broadway when he gave the middle finger to a passing Department of Transportation truck in a convoy of three vehicles and then chased after it, an NYPD spokesman said.

He caught up to it and jumped onto a diesel tank foot rail on the driver's side as it approached Eighth Avenue, police said.

The driver didn't realize the man was there and turned into a construction site, police said.

The man's backpack then got caught on a nearby metal fence and pulled him to the ground, where he was fatally run over by the truck's rear tires, police said.

"The victim was on the driver's side under the back wheel. He had on a plaid shirt and a black hat," said witness Terry Locke, 56.

"The responders came immediately. It looked like there were 50 of them, but they couldn't get him out. He was stuck underneath. They raised the back on the truck and lowered the front to try to get him," Locke added.

The man was pronounced dead at the scene, police said.

"It's very upsetting, very disturbing," Locke said.

The truck's driver stayed at the scene and wasn't immediately arrested or ticketed, police said.