A group of jewel thieves has struck numerous stores on the East Coast, efficiently cutting through security gates and cleaning out display cases in heists that have netted millions of dollars in watches, rings, earrings and necklaces, the FBI and local police say.

Police from Connecticut to Florida have reported remarkably similar break-ins by up to a half-dozen men at jewelry stores that often are located in shopping malls.

Amid indications that the thieves have begun to target the Midwest, the FBI on Thursday was announcing the formation of the "gate cutters jewelry task force" in an effort to stop them.

The thieves appear uninterested in high-end merchandise, quickly ransacking display cases after gaining entry to the store, according to police accounts.

"They actually cut the gates and went through the stores, taking whatever was there," said Deputy Chief Carl Sferrazza of the Enfield, Conn., police, describing burglaries at two jewelers at the Westfield Shoppingtown mall on the same night in May.

Police estimated the losses at $100,000. The break-ins remain unsolved, Sferrazza said.

In October, a six-person crew used a battery-powered saw to cut the gate at the Zale's Jewelry Store inside the Willow Grove Park Mall in Abington Township, Pa., according to the local police. The thieves cut power to the store, preventing them from being caught on surveillance cameras, the police said.

The burglary was similar to one at another jewelry store at the same mall in January, police said.