NEW YORK (Reuters) - Republican New York City mayoral candidate Joe Lhota, trailing far behind Democratic rival Bill de Blasio in polls, took a shot at the leader this week with a TV ad that evoked memories of the dark, violent New York of the 1970s and 80s.

The 30-second ad begins with video of a September incident in which a motorcycle gang chased and then beat the driver of a sport-utility vehicle on a Manhattan highway. A narrator reads "Bill de Blasio's recklessly dangerous agenda on crime will take us back to this," and the ad shifts to images including the city's formerly graffiti-covered subway trains and a flipped-over police car.

Those latter photos came from the 25-year period when Democratic mayors ran the city, before Republican Rudolph Giuliani, famous for his aggressive crackdown on crime, kicked off a 20-year period without a Democrat in Gracie Mansion.

Lhota was a Giuliani deputy who went on to serve as the head of New York's mass-transit agency.

De Blasio campaign officials on Thursday did not immediately respond to a call seeking comment. A campaign representative told the New York Daily News: "Lhota is right that we can't go back: we shouldn't return to the days when Republicans like Giuliani used fear tactics to divide New Yorkers against each other."

Giuliani's successor Michael Bloomberg, was elected in 2002 as a Republican and later changed his affiliation to independent.

Polls suggest the city's Democratic party has a very strong chance of breaking that streak of losses in November. De Blasio had the support of 67 percent of likely voters in a Wall Street Journal/NBC 4 New York/Marist poll released last week, which found that just 23 percent of likely voters supported Lhota.

(Writing by Scott Malone; editing by Andrew Hay)