US State Department officials expressed optimism on Thursday that new sanctions imposed on North Korea may be more effective than earlier attempts to curtain Pyongyang's nuclear program, pointing to China's apparent willingness to support them.
Two weeks before a Nuclear Security Summit in Washington, Thomas Countryman, Assistant Secretary of State for International Security and Nonproliferation, told a Senate hearing there were signs of a shift in China, North Korea's sole major ally, toward regarding its nuclear program as a threat.
"They have made clear they are ready to work with us on detailed implementation and consultation on a range of issues," he told the Senate Foreign Relations Committee.
The UN Security Council unanimously agreed to harsh new sanctions on North Korea to starve it of money for its nuclear weapons programs this month. President Barack Obama imposed sweeping new US sanctions on Wednesday.
The hearing was contentious. Senators accused Countryman and Rose Gottemoeller, Undersecretary for Arms Control, of glossing over the global nuclear security threat, particularly in Asia, and underplaying the significance of the US rift with Russia.
Russia is not attending the March 31-April 1 summit.
Republican Senator Bob Corker, the committee's chairman, said their testimony lacked "urgency and openness."
"People are not honoring treaties. Asia is in going in a very different direction than we had hoped, and yet, y'all are here telling us how, 'Gosh, we've done a wonderful job,'" Corker said.
Gottemoeller was nominated this month to be NATO deputy secretary-general, the number two post at the defense alliance. Although she does not face Senate confirmation, Corker said many lawmakers see her as too soft on Moscow, particularly over the Intermediate-Range Nuclear Forces Treaty (INF) treaty.
Washington has accused Russia of violating the treaty, which Russia denies.
"People are very concerned that you really have not been the kind of person who has pushed back heavily against Russia and has been more of an apologist," Corker said.
Gottemoeller said the administration looked for progress this year.
"I see some progress in Russia's willingness at the highest level to recommit to the treaty now and we are looking forward to moving expeditiously in 2016 to try to make some progress on this difficult matter."
She also defended her record, saying she had been pragmatic during years dealing with Moscow. "I do feel that pragmatic problem solving in the diplomatic realm is important," she said.