Police in Boston have said they thwarted a potential massacre at the Pokemon World Championship.

Security forces detained James Austin Stumbo, 27, and Kevin Norton, 18, for “threats of violence made over social media,” as they attempted to gain entry to the contest on Thursday.

A day later, police secured a warrant to search the men’s car parked a few blocks from the event. They found weapons in the vehicle: a shotgun, AR-15 assault rifle, a hunting rifle, and 250 rounds of ammunition.

Stumbo and Norton had no license to hold firearms.

READ MORE: Gunman murders guard, kills self at Manhattan federal building

The two men, from Iowa, were arrested on Saturday at a motel in Saugus, Massachusetts, and now face charges for unlawful possession of firearms and ammunition.

The search and arrest came after Stumbo and Norton posted a picture of their car and weapons in a Facebook group called “Mayhem Pokemon Crew” (the post has now been taken down).

Police rattled by spike in violent crimes across US http://t.co/qWe1hfKgn1pic.twitter.com/wXHi3ax4RN — RT America (@RT_America) August 18, 2015

The caption to the post read, “Kevin Norton and I are ready for Worlds Boston here we come!!!”

One of users in the group, Joey Faux, wrote, “Good luck!” in response, to which Norton replied, “With killing the competition?”

“Haha, yes,” Faux said.

The police were informed by Facebook users and the Pokemon International Company about the post.

“This incident is a good example of private security reaching out to their local Boston police district and relaying information to detectives and BRIC (Boston Regional Intelligence Center) analysts in order to identify the very real threat. The BPD detectives did a great job in the stop and prevention of a potential tragedy," Superintendent Paul Fitzgerald said, as cited in the official statement by Boston Police Department.

Colorado theater shooter avoids death penalty, sentenced to life in prison http://t.co/EBUz5zObkCpic.twitter.com/Y6iGwKBf8w — RT (@RT_com) August 8, 2015

The Pokemon International Company issued their statement on Sunday, saying they had been tipped off by their members about the threats.

"Prior to the event this weekend, our community of players made us aware of a security issue. We gathered information and gave it as soon as possible to the authorities at the John B. Hynes Veterans Memorial Convention Center, who acted swiftly and spearheaded communication with the Boston Police Department,” the company said.

The “potential threat” was tackled due to “quick action,” they added.

The 12th Pokemon World Championship invited hundreds of gamers from 30 countries to take part, with winners earning thousands of dollars in prize money.