Police have arrested a man who allegedly stabbed two teenage girls outside a deli in Brooklyn on Sunday, killing one of them, the NYPD said.

Veo Kelly, 20, of Bedford-Stuyvesant, faces charges of murder, assault and criminal possession of a weapon in connection with the attack, which killed 19-year-old Samyia Spain, police said.

The teens were twin sisters, according to law enforcement sources.

The stabbings happened in front of a deli on Fourth Avenue, at the corner of St. Marks Place, in Park Slope at around 2:20 a.m. on Sunday, according to police.

Law enforcement sources said Kelly became aggressive with the teens after they rejected his advances.

Mohammed Al Behar, who works at the deli, said workers got involved when Kelly became aggressive.

“They kicked the guys out and the girls stayed here. They wait for them outside, for the girls. Then the boy, he was kicking the door to come in, but they locked the door, so he couldn’t come inside," Al Behar said.

Al Behar said Kelly waited for the twins to leave, and then started a fight.

According to police, Kelly pulled out a knife and stabbed Spain in the chest and neck. The other teen was stabbed in the arm, the NYPD said.

Both were taken to a nearby hospital, where Spain was pronounced dead, police said. The other teen was listed in stable condition after the attack, according to police.

“I was so sad to see someone get hurt like that. She was 19 years old. So sad," A lBehar said. “I saw her father yesterday, and I was shaking his hand and I said, ‘Sorry for your loss. 'And he started crying.”

A GoFundMe for Spain's memorial has already surpassed $15,000 as of Friday. Family members describe her as “loving, caring and kind.” 

Kelly’s attorney information wasn’t immediately available Friday.