South Korea is in a debate about developing its own nuclear weapons, despite the United States' assurances to extend its "nuclear umbrella" to protect the Asian ally, a congressional report said Tuesday.

The Congressional Research Service also said in the report on U.S.-South Korea relations that such a move by the South could result in a series of negative consequences, including economic sanctions on Seoul and a nuclear arms race in the region.

"In the wake of North Korea's recent nuclear weapon test and satellite launch, South Korea has re-engaged in a debate about developing its own nuclear weapons capability, notwithstanding Seoul's reliance on the U.S. nuclear 'umbrella,'" the report said.

The report also noted that an opinion survey after North Korea's third nuclear test in 2013 indicated growing support in South Korea for developing an indigenous nuclear capability "amidst doubt that the United States would use its nuclear weapons to protect South Korea."

"Although U.S. policymakers have reiterated their 'ironclad commitment' to defend South Korea and have publicized B-52 and B-2 long-range bomber flights over the Korean Peninsula, some South Koreans have pointed to the failure of the United States and others to stanch Pyongyang's growing nuclear capability as justification for Seoul to pursue its own nuclear arsenal," the report said.

"Analysts point to the potential negative consequences of such a move for South Korea, including economic sanctions, diminished international standing, and the potential to encourage Japan and others in the region to follow suit, leading to a dangerous arms race in Asia," it said.

Pyongyang's nuclear and missile tests reignited calls in South Korea for its own nuclear armament, with some leading members of the country's ruling party arguing that it makes no sense to rely on the U.S. "nuclear umbrella" as the North's nuclear arsenal grows.

But the government dismissed the idea, saying it runs counter to the principle of a nuclear-free Korean Peninsula.

Adding fuel to the debate was a suggestion from U.S. Republican presidential front-runner Donald Trump that South Korea and Japan could be allowed to develop nuclear weapons for self-defense in response to the North's nuclear and missile threats.

The White House flatly rejected the idea as directly contrary to long-standing U.S. policy.

U.S. President Barack Obama also openly criticized Trump, saying the remarks about a nuclear South Korea "tell us that the person who made the statements doesn't know much about foreign policy or nuclear policy or the Korean Peninsula or the world generally."

The CRS report, meanwhile, said that U.S. officials are also concerned about the "possibility that a small-scale North Korean provocation against South Korea is more likely to escalate than it was previously, due in part to South Korea's stated intention to respond more forcefully to an attack."

"U.S. defense officials insist that the close day-to-day coordination in the alliance ensures that U.S.-ROK communication would be strong in the event of a new contingency," it said.

The report also said that Seoul's decision to begin official talks with the U.S. about the potential deployment of the THAAD missile defense system could be part of an effort to "convince China to place more pressure on North Korea, according to analysts." (Yonhap)