Weapons experts say North Korea will be capable of producing 20 nuclear bombs by the end of this year as the country ramps up its uranium enrichment. The revelation comes a week after the Hermit Kingdom conducted its fifth nuclear test, a move experts and North Korean authorities said was its most powerful yet. After evading UN sanctions for a decade, Pyongyang now has a sizable stockpile of weapons-grade material, experts warned in a new report published Monday on Johns Hopkins University’s 38 North website. Siegfried Hecker, an expert on the North’s nuclear work, says the program has likely been producing about 150 kilograms of highly enriched uranium a year—and North Korean authorities have recently stepped up production. Describing it as a “nuclear wildcard,” Hecker said the program is especially dangerous because Western experts are largely in the dark on how advanced it is.