A gang of Japanese macaques has been violently attacking people across Tokyo for the last three weeks.

There have been reports of more than 50 people being injured by the monkey attacks, which have been occurring in the Yamaguchi region. While the “leader” of the monkey group was killed by local authorities, they want more vicious ones could still be out on the streets.

"Eyewitnesses describe monkeys of different sizes, and even after the capture, we've been getting reports of new attacks," an official at the local agricultural department told AFP.

The incidents have included several break-ins through unlocked doors and windows while the injuries have included bites and scratches, according to local authorities.

“In terms of monkeys attacking people, we’ve never had incidents like this,” Kosaku Matsunaga, an official at Yamaguchi city’s Agricultural Policy Division Pest Control Room, told NBC News.

These types of monkeys usually do not become physical with people. Some believe that there must be a disruption to their habitat or that the monkeys involved in attacks are ones that have been kept captive.

“I don’t know if something is happening in the mountains. It’s hard for us humans to know,” Masato Saito, an official with the city’s agricultural policy division, said in an interview with The New York Times.

“It might be acceptable and understandable if they just ate agricultural crops alone. But if they harm humans, we need to do something,” Saito added.