BOSTON: A massive security scare was sparked by a marketing ploy for a late-night TV cartoon.

Major roads, bridges and part of the Charles River in Boston were closed off and bomb squads were sent in as authorities scrambled to deal with reports of suspicious packages yesterday.

Authorities said some of the objects looked like circuit boards or had wires hanging from them, and at least one was blown up.

But the devices were eventually declared a harmless hoax, and red-faced officials at Turner Broadcasting, the Cartoon Network's parent company, confessed that it was behind the confusion.

The packages of harmless magnetic, blinking lights were part of a promotion for the TV show Aqua Teen Hunger Force.

At least one depicted a character from the surreal cartoon making an obscene hand gesture.

Turner said they had been in place for two to three weeks in 10 US cities - Boston, New York, Los Angeles, Chicago, Atlanta, Seattle, Portland, Austin, San Francisco and Philadelphia "The packages in question are magnetic lights that pose no danger," the company said.

"We regret that they were mistakenly thought to pose any danger."

The first device was found at a subway and bus station underneath Interstate 93, forcing police to shut down the station and road.

Boston police said last night that one person had been arrested.

Peter Berdovsky, 29, of Arlington, was detained on one felony charge of placing a hoax device, and one charge of disorderly conduct, said state Attorney General Martha Coakley.

"We're not going to let this go without looking at the roots of how this happened to cause the panic in this city," she added.