A man wanted in connection with alleged threats to police officers in Philadelphia and New York City that invoked the ISIS terror group turned himself in Wednesday. 

The 36-year-old man has not been identified and no charges have been filed. However, all 36,000 NYPD officers have been ordered to be on alert for potential attacks. 

The first alleged threat, which warned that someone was planning to shoot a police officer, was called in to Philadelphia police Tuesday night. Authorities there informed their counterparts in New York that they had traced the call to Manhattan. 

Later Tuesday, the NYPD received a similar call, warning that someone planned to shoot officers in New York and Philadelphia. That caller said the man also made a reference to ISIS, though the context was not clear. 

NYPD officers were alerted to be on the lookout for the man mentioned in the phone calls, who was on parole and had an open warrant for his arrest. 

A police official told the Wall Street Journal that the man surrendered at a Bronx parole office for questioning Wednesday afternoon. 

Philadelphia Police Commissioner Richard Ross said Wednesday the tip had not been verified, adding that both police departments and the FBI were investigating the matter further. 

The alleged threats were made two weeks after Philadelphia Police Officer Jesse Hartnett was ambushed and wounded by a man using a stolen gun. The suspect, Edward Archer, said he was acting in the name of Islam when he fired more than a dozen shots at Hartnett, who was sitting in an unmarked car.