Police are looking for the man they say carried out two separate gunpoint robberies aboard a 6 train.

Authorities say both incidents happened on a northbound train approaching the Westchester Square-Tremont Avenue station.

The first robbery occurred on Christmas, just before 1 a.m. Police say the suspect held a 27-year-old man at gunpoint and demanded property. When the victim refused, the robber struck him in the face with the gun before taking his phone. EMS took the 27-year-old to the hospital in stable condition, according to authorities.

The robber struck again on Jan. 3 just after midnight. Police say he locked in on a 30-year-old man and got away with his keys and wallet, containing approximately $350 and a debit card. The second victim was not injured.

Authorities say the man was last seen wearing a black ski mask, a dark-colored jacket, dark sweatpants and white and yellow Nike sneakers.

The NYPD urges anyone with information to call its Crime Stoppers Hotline at 1-800-577-TIPS (8477).