The MTA says passengers were slashed by attackers early this morning on the Lexington Avenue subway line in Manhattan. The incident added kindling to an ongoing political battle over how to police the subways.

Interim New York City Transit President Sarah Feinberg is blaming Mayor de Blasio for the attacks, saying they might been prevented if he'd added more cops underground. She then name checked 5 mayoral candidates who said they'd do it.

Her comments followed Thursday night's first official Democratic primary debate, where candidates were asked about crime.

Some government watchdogs say it was inappropriate for the MTA to back any candidates.

But others says the MTA - which is controlled by the governor - is never free of politics.

The city has 3,000 police officers currently assigned to the subways, and it pledged to send more uniformed volunteer officers last week.