Cops busted two teens with loaded guns in The Bronx, police said Sunday.

The plainclothes narcotics officers first spotted a pair of teens around 4:20 p.m. Thursday walking in an alleyway near the rear of a building on Creston Avenue near East 182nd Street in Fordham Heights, cops said.

The officers watched as 17-year-old Samson Walston pulled a .45-caliber American Standard firearm from his waistband and stuffed it under a trash bag, police said. Cops arrested Walston and his buddy, also 17, as soon as they exited the alleyway.

A 15-year-old boy who was with the two other teens, briefly got away and allegedly tried to ditch two guns he was carrying, but cops arrested him after a short pursuit.

Cops recovered his guns — a .40-caliber Glock 23 and a 9mm Glock 19 — as well as the weapon Walston hid under the trash bag, police said.

Walston and the 15-year-old boy, whose name was not released because he is a minor, were charged with possession of a loaded firearm. The other 17-year-old boy was later released from police custody.