President Barack Obama said Thursday that the United States will act firmly against any nuclear proliferation activities by North Korea.
In a speech to the Australian Parliament, Obama said the transfer of nuclear material by North Korea to other nations would be "considered a grave threat to the United States and our allies."
The United States will "hold North Korea fully accountable for the consequences of such action," he told the parliament while outlining U.S. plans to stay invested across Asia and Australia, despite budget cuts back home.'
Obama's warning comes amid efforts to restart negotiations with North Korea on dismantling the nation's nuclear program.
North Korea has tested two nuclear devices since 2006, and is believed to be working toward mounting a bomb on a long-range missile designed to reach the U.S.
U.N. sanctions imposed on the country prohibit North Korea from engaging in nuclear and ballistic activity and from exporting atomic technology to other nations. In a report last year, U.N. experts outlined suspicions that Pyongyang was involved in banned atomic activities in Iran, Syria and Myanmar, including selling nuclear and missile technology.
Five countries, including the U.S., had been negotiating with North Korea to provide the nation with much-needed aid in exchange for disarmament. North Korea abandoned those talks in 2009 after the U.N. strengthened sanctions against Pyongyang, and later that year, Pyongyang announced it was also enriching uranium.
North Korea says its uranium enrichment program is meant to provide fuel for a light-water reactor that the country is building at its main Yongbyon nuclear complex. At low levels, uranium can be used in power reactors, but at higher levels it can be used to make nuclear weapons.
Concerns about North Korea's atomic capability took on renewed urgency in November 2010 when a visiting American scientist was shown a uranium enrichment facility.
Last week, North Korean state media said "the day is near at hand" when the reactor will come into operation.
Washington is concerned about reported progress on construction of a reactor, State Department spokesman Mark Toner said Tuesday. He said construction of a light water reactor would violate U.N. Security Council resolutions.
North Korea has expressed its willingness to rejoin the nuclear talks. Senior diplomats from the United States, South Korea and Japan were to meet Thursday to discuss North Korea on the sidelines of a regional forum in Bali, South Korean officials said.