An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

Muslim women light candles during the “EarthHour” in Jakarta, Indonesia, on March 23, 2013. Hundreds of people observed the global event that encourages people to turn off their lights for 60 minutes. (Photo by Dita Alangkara/Associated Press)

Afghan National Army (ANA) soldiers sit waiting to return their weapons after a day of traning at the Kabul Military Training Center (KMTC) October 3, 2010 in Kabul, Afghanistan. There are between 5,000 to 7,000 troops on the training facility in eight-week cycles trained by the coalition forces to ultimately take over the role of military operations in the country. (Photo by Paula Bronstein/Getty Images)

The hot air balloon “Hopper T Frog” from Park City, Utah, peeks over the red rock cliffs during the 23nd Annual Red Rock Balloon Rally at Red Rock State Park December 6, 2003 near Gallup, New Mexico. (Photo By Douglas Tesner/Getty Images)

A soldier helps another with her ear protection at the Terningmoen Camp in Elverum, Norway on March 23, 2017. Soldiers demonstrate their skills and tactics during a contract drill as they train to become part of the world's first all-female special forces unit, the Jegertroppen or “hunter troops”. (Photo by Carolina Reid/NBC News)

A Thai Buddhist monk prepares to take part in a televised anti-plague prayer at Wat Traimit Temple (Temple of the Golden Buddha) amid lockdown restrictions to contain the spread of the COVID-19 coronavirus in Bangkok on March 25, 2020. The monks at Buddhist temples nationwide chanted the Rattanasoot (Seven Legends) Prayer in unison in a bid to boost public morale amid the epidemic of COVID-19 coronavirus. (Photo by Mladen Antonov/AFP Photo)

A woman returns home carrying vegetable on her back (foreground) while other farmer works on vegetable field (background) during the 43rd day of the lockdown imposed by the government as a preventive measure against the spread of COVID-19 coronavirus, in Kathmandu, Nepal on Tuesday, May 5, 2020. (Photo by Rojan Shrestha/NurPhoto via Getty Images)

Ukrainians attend an open military training for civilians on a training range in Kiev, Ukraine, 06 February 2022. According to a survey conducted by the Kiev International Institute of Sociology (KIIS) from December 2021, 50.2 percent of Ukrainians said they would resist in case of a Russian military intervention into their city, town or village. Every third respondent to the poll said they were ready to engage in armed resistance, and 21.7 percent said they were ready to participate in civil resistance actions. (Photo by Sergey Dolzhenko/EPA/EFE/Rex Features/Shutterstock)