The masked, knife-wielding serial robber with a penchant for hitting ice cream parlors and sandwich shops now has struck 14 times, with two new holdups in North Merrick and Lynbrook on Saturday night, Nassau police said Sunday.

The two latest — an attempted robbery of a Subway sandwich shop in North Merrick and the robbery of a Lynbrook TCBY frozen yogurt store — fit the pattern of the dozen others believed to have been committed by the same suspect in both Suffolk and Nassau since mid-February, said Nassau police Det. Lt. Richard LeBrun, a department spokesman.

No one has been injured in any of the heists, during which the robber has brandished a machete or large kitchen knife, but cops have said the suspect should be considered extremely dangerous and that store clerks should comply with his demands for cash.

Saturday’s robberies began about 7:09 p.m., when the suspect went into a Subway at 1341 Jerusalem Ave. in North Merrick and displayed a large kitchen knife as he approached a 55-year-old male employee and demanded money from the cash register, police said.

The employee pressed the panic alarm, and the man ran away with no proceeds, police said. The employee was the only person inside the Subway, police said.

Two hours later and eight miles away, police said, the same male suspect walked into the TCBY yogurt shop at 653 Sunrise Hwy. in Lynbrook and demanded that a 19-year-old female employee give him money from the register.

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After obtaining an undisclosed amount of cash, the robber left the store and was last seen walking toward Broadway, police said. Two employees were inside the store, but there were no customers.

Witness descriptions of the suspect mirrored those in previous heists. Police said Sunday the suspect was described as male, between 5-foot-5 and 5-foot-8, wearing a dark hat with a brim, dark jacket, blue jeans, gloves and a scarf covering his face.

Subway sandwich shops, Carvels and Dunkin’ Donuts have been the robbery suspect’s stores of choice, and he’s mostly struck at night — though he changed the script last Tuesday, when he walked into The Barn on Belmont Avenue in West Babylon and ran off with cash about 1:45 in the afternoon. He also hit up a GameStop store in Merrick that night, police said.

Police won’t say how much money he’s stolen so far in the four Suffolk and eight Nassau robberies, to avoid enticing other would-be thieves looking for quick cash. The robber also unsuccessfully held up a Dunkin’ Donuts in Seaford on Feb. 15, in addition to Saturday’s attempted robbery of the North Merrick Subway.

The Crime Stoppers reward in the case is up to $10,000, with $5,000 being offered in both counties.

Detectives request anyone with information regarding any of the heists to call Nassau Crime Stoppers at 800-244-8477 or Suffolk Crime Stoppers at 800-220-8477. All callers will remain anonymous.

Island residents interviewed on Easter Sunday, a day after the two most recent holdups, said the robberies have made them more cognizant of their surroundings. But they continued to shop at the type of ice cream shops and convenience stores that the robber has favored.

“It makes me afraid when I walk in,” Long Beach resident Erika Linzer, 64, said as she went into a 7-Eleven in Copiague on Sunday.

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Jason Vargas, 30, of Queens, said he grew up in a rough neighborhood, so news of the robberies left him unfazed at the thought of shopping at Long Island convenience stores.

“I wouldn’t think twice about it,” said Vargas, who was at a 7-Eleven in Farmingdale on Sunday afternoon.

At a Starbucks next to the Lynbrook TCBY that was robbed Saturday, customers said the holdups were unnerving, but they remained optimistic that the suspect eventually will be caught.

“It’s pretty scary,” said Chrisette Michele, who owns a clothing store in Valley Stream.

In North Merrick, Maribel Calcagni, who lives across the street from the Subway targeted Saturday night, described the attempted robbery as “obviously concerning. We don’t want any problems.”

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Carolyn Foskey, 49, of Amityville, had a simple message as she left a Dunkin’ Donuts in the village Sunday.

“I’m not afraid,” she said, adding that police need to step up patrols to catch whoever is behind the robberies.

Nassau and Suffolk police have indeed increased patrols — using squad cars and undercover officers — near businesses like the ones held up. Police also have advised business owners to keep their stores well-lit and remove signage from their windows so officers can have a clear view of the inside.

Still, Nancy Bott, 52, of Copiague, who was stepping out of the North Merrick Dunkin’ Donuts, said increasing law enforcement for so many stores is not feasible.

“It’s too many to patrol,” she said.

With Deon J. Hampton, Lisa Irizarry and Rachel Uda