President Donald Trump raised eyebrows Wednesday by putting an unusually specific number on how many nuclear weapons North Korea possesses: 57.

The U.S. president did not provide the source for this number when addressing reporters, leaving questions over whether it reflects intelligence assessments, an estimate of operational warheads or simply a figure drawn from another calculation.

Nevertheless, the figure is broadly in line with some of the latest estimates of North Korea’s nuclear arsenal, even as South Korea offered a markedly higher assessment just hours later. 

The differing numbers underscore the uncertainty surrounding the DPRK’s nuclear capabilities, as well as