President Obama vowed his government would "act firmly" to ensure that North Korea cannot transfer nuclear material or systems to other nations or extremists, Agence France-Presse reported on Wednesday.
"The transfer of nuclear materials or material by North Korea to states or non-state entities would be considered a grave threat to the United States and our allies," Obama said in remarks to Australian lawmakers in Canberra. "We would hold North Korea fully accountable for the consequences of such action."
Obama said the U.S. military would continue to have a robust footprint in the region and on the Korean Peninsula.
China has demonstrated its potential as a useful "partner" in blocking North Korean weapon exports and lowering regional tensions, Obama said. "We'll seek more opportunities for cooperation with Beijing."
The Obama administration on Tuesday noted its concern over the North's construction of a light-water atomic reactor site at the Yongbyon nuclear complex, AFP reported. The project has progressed rapidly since last November, when U.S. nuclear-weapons experts were given a tour of the structure, according to an earlier report.
Pyongyang's refinement of uranium and "construction of a light-water reactor violate U.N. Security Council resolutions as well as their commitment to the 2005 joint statement," said State Department spokesman Mark Toner, referring to the regional agreement that would reward Pyongyang's permanent denuclearization with massive amounts of foreign aid and security guarantees.
"Certainly, we're concerned about the matter," he said.
Though North Korea claims its uranium-enrichment program is focused on producing fuel for its unfinished reactor, Washington and other governments suspect the program is actually aimed at generating fissile material for warheads.
In Indonesia, U.S. Assistant Secretary of State Kurt Campbell was scheduled to meet at the East Asia Summit on Thursday with South Korean nuclear negotiator Lim Sung-nam and Japanese nuclear negotiator Shinsuke Sugiyama to discuss their governments' allied posture on North Korea's nuclear program, the Yonhap News Agency reported.
"The three diplomats are expected to jointly assess the outcome of last month's bilateral meeting in Geneva between the U.S. and North Korea, and exchange views on the direction of future dialogue," an unidentified South Korean official said.