Updated

North Korea said Wednesday it is making rapid progress on work to enrich uranium and build a light-water nuclear power plant, increasing worries that the country is developing another way to make atomic weapons.

Pyongyang's Foreign Ministry said construction of an experimental light-water reactor and low enriched uranium are "progressing apace." The statement added that North Korea has a sovereign right to the peaceful use of nuclear energy and that "neither concession nor compromise should be allowed."

The statement by an unidentified Foreign Ministry spokesman was carried by the official Korean Central News Agency.

Concerns about North Korea's atomic capability took on renewed urgency in November 2010 when the country disclosed a uranium enrichment facility that could give it a second route to manufacture nuclear weapons, in addition to its existing plutonium-based program.

North Korea has been building a light-water reactor at its main Yongbyon nuclear complex since last year. Such a reactor is ostensibly for civilian energy purposes, but it would give the North a reason to enrich uranium. At low levels, uranium can be used in power reactors, but at higher levels it can be used in nuclear bombs.

Earlier this month, North Korean state media said "the day is near at hand" when the reactor will come into operation. Washington worries about reported progress on the reactor construction, saying it would violate U.N. Security Council resolutions.

State Department spokesman Mark Toner on Wednesday said that reactor construction and uranium enrichment also violates commitments on denuclearization North Korea made in 2005. "We remain concerned about it," he said in Washington.

U.S. Secretary of State Hillary Rodham Clinton, speaking to reporters Wednesday at an international aid forum in the South Korean port city of Busan, didn't address the North's statement on uranium. She called the U.S.-South Korean alliance strong and mentioned the recent one-year anniversary of North Korea's artillery attack on a front-line South Korean island that killed four people.

"Let me reaffirm that the United States stands with our ally, and we look to North Korea to take concrete steps that promote peace and stability and denuclearization," Clinton said.

Five countries, including the United States, have been in on-again, off-again talks with North Korea to provide Pyongyang with aid in exchange for disarmament. North Korea pulled out of the nuclear disarmament talks in early 2009 to protest international condemnation of its prohibited long-range rocket test.

In recent months, North Korea has repeatedly expressed its willingness to return to the talks, and tensions between the Koreas have eased. Diplomats from the Koreas and the United States have had separate nuclear talks, and cultural and religious visits by South Koreans to the North have resumed.

South Korean and U.S. officials, however, have demanded the North halt its uranium-enrichment program, freeze nuclear and missile tests and allow international nuclear inspectors back into the country before resuming negotiations.

China, North Korea's main ally and benefactor, did not respond directly to Pyongyang's latest claims but appealed for an early resumption of the nuclear disarmament talks.

"Under the current circumstances, we hope all the relevant parties will make joint efforts to resume the six-party talks as soon as possible," Chinese Foreign Ministry spokesman Hong Lei said in response to a question at a daily media briefing Wednesday. "All the relevant issues of concern can be discussed within the framework of the six-party talks."

The North Korean statement accused the United States and its allies of "groundlessly" taking issue with the North's peaceful nuclear activities. They are "deliberately laying a stumbling block in the way of settling the nuclear issue on the Korean peninsula through dialogue and negotiations," the statement said.

Kim Yong-hyun, a professor at Seoul's Dongguk University, said the North's statement appeared aimed at applying pressure on Washington and the international community to rejoin the nuclear disarmament talks quickly. "North Korea is expected to step up its rhetoric," he said.

Also on Wednesday, Seoul's Unification Ministry said a South Korean official who recently traveled to the North to help monitor the distribution of flour by a civic group confirmed that the aid has reached North Korean children. Some international donors have been wary of providing aid out of concern it could be diverted to the military and top government officials.