A knife-wielding woman slashed another female commuter as tensions flared during the Thursday morning commute in downtown Brooklyn, and then turned herself in a short time later — only to be cut loose in court, cops and prosecutors said.

The victim, 44, had just gotten off an R train at the Jay Street-MetroTech station around 9:40 a.m. when she and Jahlayah Blondel, 26, got into a heated argument, according to authorities and sources. 

The clash turned violent when Blondel — a stranger to the victim — allegedly pulled out the blade and cut her on the left shoulder, police said. 

Jahlayah Blondel, 26, allegedly cut the 44-year-old victim on her shoulder when a fight erupted after the victim got off an R train at Jay Street-MetroTech, police said. Paul Martinka

The victim was taken to NYU Langone Health—Cobble Hill with minor injuries, cops said. 

Blondel, of Staten Island, initially fled the scene and ditched the knife, police said. 

But she then turned herself in around 10:10 a.m. at the NYPD’s Transit District 30 headquarters, located inside the Hoyt/Schermerhorn Street station, police said. 

She was charged with felony and misdemeanor assault, menacing, criminal possession of a weapon, attempted assault and harassment, according to a complaint filed in Brooklyn Criminal Court. 

The victim was hospitalized in stable condition, while her attacker — who ditched the knife — later surrendered to cops, police said. Paul Martinka

Blondel was also charged with possession of an imitation pistol that cops found in her bag, prosecutors said. 

The alleged slasher — who cops say has no previous arrests in the Big Apple — was released on her own recognizance by Criminal Court Judge Masateru Marubashi, over prosecutors’ request for $10,000 cash bail or $20,000 bond, according to the DA’s office. 

The attack came just over 12 hours after a 17-year-old boy was slashed with a box cutter inside a Harlem subway station, cops said.

The victim was cut on his left wrist around 9:25 p.m. Wednesday during a feud with two teen boys and two teen girls on the B and C train platform at West 135th Street, according to authorities.He was taken to Harlem Hospital, where he is listed in stable condition.

The young suspects fled the scene and remain at large.