North Korea's nuclear test last month rattled South Korea so much that some politicians are calling it an inflection point, with some now arguing openly that Seoul should develop nuclear weapons.

South Korean Foreign Minister Yun Byung-se told foreign officials that the North's nuclear test last month, its second of the year and most powerful yet, is being viewed by many in his country as "a kind of Sept. 11 attack," the Yonhap news agency reported Sunday, citing official sources. The Sept. 11, 2001, terrorist attacks on the U.S. defined security concerns there for a generation.

Yun "has been comparing the Sept. 9 test to the al-Qaida attack in recent meetings with foreign officials," a diplomatic source was quoted as saying. The source, who declined to be identified, said the purpose of linking the two events was to drive home the view in the South that "circumstances are extremely grave" in the wake of the North's nuclear and missile tests.