North Korea may be offering nuclear talks pretty much without preconditions, a U.S. expert who took part in negotiations with Pyongyang has said.

Former U.S. State Department North Korea specialist Robert Carlin said Pyongyang this month set out five preconditions that demand little of Washington but appear to be a serious offer to place its arsenal on the table.

Writing on the Pyongyang-watching website 38 North, Carlin said the announcement was met with silence on the U.S. side, perhaps because Washington was preoccupied at the time with trumpeting new sanctions against North Korean leader Kim Jong Un.