A knife-wielding maniac with a history of mental illness and 87 prior arrests is wanted in connection with at least two stabbings in the subway this week, The Post has learned.

Cops searching for Jamar Banks were warned to use “extreme caution” when encountering him because he is believed to be armed with “a large knife,” according to a message sent to police officers and obtained by The Post.

Banks, 52, is known to frequent the No. 2 and No. 5 subway lines, authorities said in the message.

He’s being sought in connection with stabbings on Jan. 1 and Jan. 2, according to the NYPD.

A surveillance photo allegedly shows Banks holding the knife in gloved hands.

“He has a very very lengthy arrest history,” a police source said. “It looks like he rides the rails back and forth.”

Banks is wanted for allegedly approaching a 31-year-old man from behind on a 2 train at 14th Street and Seventh Avenue in Manhattan on Wednesday and starting an argument, before stabbing him in the back and running away.

He’s also suspected of knifing an off-duty MTA cleaner in the back and armpit around 6 a.m. Thursday, after starting an argument with the victim on a northbound 6 train platform at the Pelham Bay station in the Bronx, police said.

The attacker fled after the stabbing.

Both victims were taken to hospitals in stable condition. 

Banks’ rap sheet includes arrests for charges including attempted murder, weapons possession, assault, criminal trespassing, turnstile jumping and petty larceny, police sources said.

Banks allegedly stabbed a man in the leg with a kitchen knife on a Manhattan subway around 11 p.m. on Oct. 19, 2022, cops said.

The 26-year-old victim told police he boarded the northbound No. 2 train at Fulton Street and that his attacker got on at 72nd Street and attempted to sit on his girlfriend’s lap, police said.

When the victim asked Banks to step back, Banks allegedly pulled out a knife and stabbed him in the lower left leg. 

The officers who responded applied a tourniquet and the victim was taken to a hospital, cops said.

Banks was arrested on Dec. 14 for the attack and charged with assault with intent to cause injury with a weapon. It wasn’t immediately clear what happened to the case after that.

In June 2015, Banks was accused of bursting out of a McDonald’s bathroom at 14th Street and Sixth Avenue in Manhattan and stabbing a man who had knocked on the door to see if the facility was occupied, the police sources said. 

In June 1997, Banks was charged with attempted murder after a man bumped into him, allegedly prompting Banks to shoot the man in the leg, the sources said.

The victim told cops he was walking on East 226th Street in the Bronx when a man bumped into him. He kept walking and was about to go into a store when Banks allegedly opened fire, the sources said.

Banks, who was 24 at the time, was charged with intent to commit murder, assault with intent to cause serious injury with a weapon, criminal use of a firearm in the first degree, criminal possession of a weapon in the second degree, cops said. 

The outcome of the case wasn’t immediately clear.