An armed Bronx man barricaded himself inside his apartment, fired at cops through his front door and set a blaze inside the building during a lengthy standoff with police Wednesday.

Samuel Foster, 39, allegedly fired six shots at police when they tried to enter his University Heights apartment — with three bullets striking a police ballistics shield, police sources said.

He surrendered to cops on his fire escape around 1 p.m. — nearly one and a half hours after police responded to the scene on a call of an emotionally disturbed person.

Foster was charged with attempted murder of a police officer and criminal possession of a weapon, the sources said.

They said he was taken to a local hospital for a psychiatric evaluation.

“The whole building was flooded with cops,” said witness Julian Ramirez, 30, who said he was visiting a friend in the building.

“It was like a military assault,” he said. “Then I smelled smoke coming in through the window and the fire department showed up. I felt like the whole world had gone crazy.”

“Then, from out my window, I heard shouting,” Ramirez said. “It was the guy going, ‘I’m unarmed, I’m unarmed.’ He must have shouted it 1,000 times. The next thing I heard was they arrested him and took him away in an ambulance.”

Dramatic photos from the scene show Foster face down on the fire escape screaming with his hands out — before cops crime through a window and handcuff him.

He can still be seen yelling as he’s being cuffed. Another photo shows a half-dozen police officers on the roof of the building at 135 W. 183rd Street during the standoff.