The reported test comes after North Korea tested two types of underwater-launched strategic cruise missiles on Wednesday, in what is believed to be a push to bolster its naval capabilities.
North Korea has legally enshrined its status as a nuclear-armed state, with its leadership repeatedly declaring the country's atomic arsenal permanent and irreversible.
In August, Trump told reporters that North Korean leader Kim Jong-un had "57 very powerful nuclear weapons" as he once again touted the pair's relationship.