A Queens man faces drug trafficking charges after Methuen police arrested him, seizing a gym bag containing 15 kilos of fentanyl worth approximately $1.2 million.

Police responded to a 911 call for a report of a man with a gun on Glenn Avenue yesterday at 8:41 a.m. and encountered 32-year-old Robinson Rojas-Rosario, according to Methuen police Lt. Michael Pappalardo.

No gun was found on the scene, but Rojas-Rosario had a black Nike gym bag on him, Pappalardo said.

“Officers opened the bag and found what appeared to be 15 packages, they observed the packages were suspected fentanyl, marked ‘China White,’ ” Pappalardo said. “The packages weighed about 1 kilo apiece. The estimated street value is $1.2 million.”

Rojas-Rosario will be arraigned today in Lawrence District Court on drug trafficking charges, Pappalardo said. He was not previously known to Methuen police. Along with the fentanyl, police sized $560 in cash and a pill bottle with other, unidentified drugs, Pappalardo said.

“China White” is an opioid-based street drug manufactured in China and sold in the United States, Pappalardo said.

Police are investigating why Rojas-Rosario was in Methuen and are “exploring the possibility” of the 32-year-old being a major drug dealer, Pappalardo said, adding the suspect was riding in a taxi cab this morning when the call came in. The lieutenant said the cab driver was not involved, and police have not released any information about the 911 caller who provided a “detailed” description of Rojas-Rosario.

Pappalardo said this is one of the largest drug busts Methuen police have made.

“It’s substantial,” he said. “It will definitely have an impact in the area as far as supply and demand is concerned.”

The arrest comes as Methuen and state police are investigating how a 10-month-old girl in the city came into contact with fentanyl, resulting in hospital staff having to resuscitate her twice when she stopped breathing.

Police say there is no known connection between the scare involving the baby and the seven-figure drug bust.