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)

Jorge (2nd R), 31, who is among members of lesbian, gay, bisexual and transgender (LGBT) community and his brother Paulo, 28, (R) laugh at Arouche Square in downtown Sao Paulo, Brazil, November 20, 2016. (Photo by Nacho Doce/Reuters)

A Bangladeshi girl watches from a nearby building after a five-story building was raided by police in Dhaka, Bangladesh, Tuesday, July 26, 2016. Police in Bangladesh's capital raided a five-story building Tuesday that was used as a den by suspected Islamic militants, killing nine of them, the country's police chief said. Police said they belonged to a Bangladeshi group blamed for an attack on a Dhaka cafe earlier this month in which 20 hostages, mostly foreigners, were killed and had been planning another large-scale assault. (Photo by AP Photo)

Christ the Redeemer is seen from the Vista Chinesa (Chinese View) during sunrise in Rio de Janeiro, Brazil, May 4, 2016. Rio de Janeiro is a marvel and a mess all at once. When it hosts the first ever Olympics in South America, starting Aug. 5, visitors will see a city whose stunning topography – stark, verdant mountains loom over packed and playful beaches – competes only with the drama of daily life here. (Photo by Ricardo Moraes/Reuters)

Participants perform during a Latin dance competition in Tel Aviv, Israel July 18, 2015. Some 66 dancers took part in the contest on Saturday, selecting a winning couple to represent Israel in the finals of The World Latin Dance Cup, which will be held at the end of the year in Miami. (Photo by Amir Cohen/Reuters)

A rider holds on as a bull tries to throw him during the Bull Ride Spectacular on the first day of the 2014 Deni Ute Muster at the Play on the Plains Festival grounds on October 3, 2014 in Deniliquin, Australia. (Photo by Mark Kolbe/Getty Images)

Geology Professor Fetullah Arik takes measurements next to a large sinkhole on June 03, 2021, in Karapinar, Turkey. In Turkey’s Konya province, the heart of the country's agriculture sector, extreme drought conditions over the past two years are taking a heavy toll on farmers and the land. (Photo by Chris McGrath/Getty Images)

A biker carrying huge bags of recyclables travels on a street outside Phnom Penh, Cambodia on Saturday, March 27, 2021. (Photo by Heng Sinith/AP Photo)