Vershbow earlier this month labelled North Korea a "criminal regime" engaged in money laundering, drug running, counterfeiting and other illicit activities.

"He must be a tyrant wearing a mask of diplomat since he recklessly make imprudent and provocative remarks," Rodong Shinmun, newspaper of the North's ruling Workers Party, said in a commentary monitored by Yonhap.

The North's official Korean Central News Agency demanded earlier that the "bitchy and malignant" US envoy, who took over in Seoul in October, be sacked.

South Korean officials fear the US envoy's harsh rhetoric might foil their efforts to end the stalemate in nuclear disarmament talks.

The North refuses to return to the six-nation nuclear talks, citing US sanctions imposed on it over allegations of counterfeiting and money laundering.

At the six-party talks in September, North Korea agreed in principle to dismantle its nuclear weapons program in exchange for diplomatic and economic benefits and security guarantees.

But at the last session in November it said US sanctions were blocking any progress.