If Washington and Pyongyang are unable to resume diplomacy and ultimately fail to reach a nuclear deal, the responsibility "should lie squarely with the U.S.," one of North Korea's top officials said on Friday, according to a report by South Korea's Yonhap News Agency.

The remark, made by Choe Son Hui, the DPRK's First Vice Minister of Foreign Affairs, was the latest comment in a wave of warnings, insults, and threats from members of North Korean senior leadership in recent days — all seeming to send a message to the U.S. that a diplomatic breakthrough with Pyongyang is not going to be easy.