Librado Romero/The New York Times

In the continuing hot dog wars in front of the Metropolitan Museum of Art, the military men have returned to the sidewalk.

The two men, Armando Crescenzi and Harold Dalton, are former soldiers who now hold a position on the museum’s plaza, brandishing veteran vending permits that they say give them the right to sell hot dogs to the throngs of hungry tourists and visitors in front of the entrance to the museum.

Their arrival has upset a peaceful period there during which three other vendors operated in relative harmony: a hot dog cart, a gourmet pretzel stand and an upscale seller of cupcakes and milkshakes.

The pretzel and cupcake carts pay the city about $100,000 each to operate there, but the hot dog operator pays nothing. He is a former Marine, Dan Rossi, who invokes a 19th-century state law that allows disabled veterans to sell in some areas of the city where other vendors must pay to occupy.

Since 2007, Mr. Rossi has been battling city authorities and clinging to a spot directly in front of the museum steps at Fifth Avenue at 82nd Street. It is regarded as perhaps the most lucrative location for selling hot dogs in Manhattan. It is so coveted that the city once charged more than half a million dollars a year for vending rights there.

But now two additional veteran carts have arrived, invoking the same state law. They have set up on either side of the broad steps. The new cluster of carts is frustrating museum and city officials, and creating competition and bickering among the vendors.

Mr. Rossi argues that he owns his cart and employs several needy veterans as grill men. The other carts are owned by nonveterans whom Mr. Rossi accuses of simply “renting” veterans to make them legal.

“They’re rent-a-vets,” said Mr. Rossi, 62, referring to Mr. Crescenzi and Mr. Dalton.

The museum is on Parks Department property, and department officials say state law allows disabled veterans to sell near the curb, but not on the museum plaza. Since much of the curb in front of the museum is designated as bus stops and taxi stands, department officials have allowed only two spots for veteran vendors, one directly in front of the museum steps and one south of the steps.

For the past four years, Mr. Rossi has occupied the spot, selling $2 hot dogs and $1 bottles of water.

Mr. Rossi said that in July, when the two carts appeared, he filed a complaint with the city’s Department of Investigation contending that Mr. Crescenzi and Mr. Dalton were misusing the veteran law.

He said the complaint was referred to the Health Department and no action was taken.

“They have a scam,” he said. “One guy owns the cart and hires the vet to sit there with his permit, and that’s not how it’s supposed to work.”

A spokeswoman with the city’s Law Department said that the vending space directly in front of the museum steps — the one where Mr. Rossi sets up — is available on a “first come first served” basis.

When a reporter visited the location on Sunday, Mr. Crescenzi was napping in a portable chair next to a food cart. Mr. Crescenzi was hardly dressed for grill work: he wore loafers, slacks, a blazer and a fedora.

But he offered no apologies. The food cart was a partnership between him and an operator, he said. The operator — whom he would not name — oversees the food sales, while his own duties involve handling the licensing and administrative issues, including the daily summonses they receive from the Parks Department for vending there. By law, he has to stay with the cart with his permit when it is open for business, he said.

“They got the cart, I got the permit: it’s a partnership,” he said. “I’m 50 percent of this operation, even if I show up and take a nap.”

Mr. Dalton described a similar partnership behind his food cart.

The two said they were disabled veterans who have been forced out of other spots around the park by city authorities and have started a coalition of military veterans who work as vendors, called Veterans First.

Both men said they have gotten tickets every day since they arrived in front of the museum and intended to fight the citations in court.

When a Parks Department enforcement sergeant approached on Sunday, the men exchanged cheerful pleasantries and the veterans handed over their identifications and received citations for “failure to comply” with an officer’s directions.

Mr. Crescenzi said Mr. Rossi was still making the lion’s share of profits at the location. He pointed to Mr. Rossi’s cart with its long line of customers.

“He’s the real rent-a-vet,” he said. “He’s a millionaire who wants this whole area for himself.”

Derek Hunt, one of the owners of the Cake and Shake cart, said that he agreed to pay roughly $9,000 a month for the spot, with the understanding that only the pretzel cart and Mr. Rossi would sell there.

Since the arrival of the additional two veteran carts, Mr. Hunt said, “My revenue has been driven down 40 percent.”

He said that for the past year Parks Department enforcement officers would escort any additional vendors away from the museum, but this has stopped.

“I got hundreds of thousands of dollars tied up in my cart and these guys could put me out of business,” he said. “Everyone I ask to enforce the law says they don’t want to be the one who kicks a veteran out. This law was created to help veterans who want to work. Not to make them straw vets, set up next to a cart like they’re inflatable.”

The competition shows no sign of abating. On Saturday, another veteran started selling in front of the museum.