Sworn robot enemy Mayor Bill de Blasio is ramping up his war on machines, after a FedEx delivery bot appeared suddenly on the streets of Manhattan last week.

In a sternly worded letter sent to the company on Monday, the mayor's Department of Transportation demanded the unmanned vehicle roll itself out of town—or risk a possible municipal robo-hunt.

"You are hereby directed to immediately cease and desist operating your SameDay Bots on the streets and sidewalks in the City of New York," reads the letter, signed by DOT Deputy General Counsel Susan Pondish. "Failure to do so may result in the seizure of property, notices of violation and/or the commencement of legal actions."

Unveiled by FedEx earlier this year, the SameDay bots use LIDAR sensors to steer around vehicles and pedestrians, with the goal of handling short-distance deliveries. Each machine has six wheels, the front two of which are slightly smaller, allowing them to ascend stairs. In the wild, they have been seen performing some sort of mating dance.

It's unclear whether FedEx planned to begin testing the product in New York City, as they're currently doing in other cities. The vehicles seem to have been part of a promotional event held last week.

But their overnight appearance has invited debate about the handling of automated delivery vehicles—whether they might effectively reduce growing e-commerce congestion, or serve to ultimately crowd out pedestrians while undercutting workers.

In their letter, the city claimed the robot couriers are both a threat to couriers and in violation of a host of local laws, including a prohibition on motor vehicles operating without a human minder—something that some tech companies are hoping to change.

(The city's public threats also raise another pressing question: If the robots prove uncooperative, could our local officials actually defeat them? Are we really that confident that the same DOT that's spent the last three years installing, then ripping out, then re-installing a new bike lane on Dyckman Street would prevail over a fleet of next generation automatons? For that matter, could you best the SameDay Bot, mano y robo? Considering the way things are going, one begins to wonder if de Blasio should be approaching our future overlords a bit more diplomatically.)

In a statement to Gothamist, mayoral spokesperson Will Baskin-Gerwitz didn't seem too worried: "Today’s letter will hopefully be the end of this experiment, but we’re prepared to take further steps if FedEx isn’t willing to get them off our streets."

CORRECTION: An earlier version of this story referred to a "swarm" of FedEx robots on the streets of Manhattan. A spokesperson has pointed out that there was only one robot. We regret the error.