CAMBRIDGE, Mass. (AP) — Two construction workers suffered serious injuries Monday morning when they were stabbed by a coworker during a dispute that apparently stemmed from a debt, police said.

Police responded to a construction site in Cambridge at about 7:15 a.m., Deputy Superintendent Pauline Wells said at a news conference at the scene.

The altercation began on the third floor of an apartment building under construction when the suspect stabbed one victim in the legs, she said.

“The assailant kept saying that ‘he owes me, he owes me,’ ” Wells said.

Another worker was stabbed in the back when he intervened, she said.

Workers held down the suspect until police arrived, she said.

All three men were in their 20s but no names were made public. They worked for a subcontractor.

Wells praised workers who helped detain the suspect and rendered aid to the two injured men until first responders arrived, perhaps saving at least one life, she said.

The victims’ injuries are serious but not conisdered life-threatening, Cambridge police said in a tweet.

The suspect faces several charges including two counts of armed assault with intent to murder, she said.

Police also recovered a knife at the scene.