U.S. Secretary of State Hillary Clinton reiterated on Wednesday that the United States will defend South Korea and Japan when the two countries face threats from the Democratic People's Republic of Korea (DPRK).

"I want to underscore the commitments the United States has and intends always to honor for the defense of South Korea and Japan," Clinton told reporters two days after the DPRK conducted its second nuclear test since 2006.

Noting that the DPRK was behaving in a "provocative and belligerent" manner toward its neighbors and there were consequences to such behavior, Clinton urged Pyongyang to return to the six-party talks on abandoning its nuclear programs.

Also on Wednesday, White House spokesman Robert Gibbs described the latest underground nuclear test by the DPRK as "saber-rattling and bluster."

"Threats won't get North Korea the attention it craves. Their actions are continuing to further deepen their own isolation, from the international community," Gibbs told reporters.

The DPRK announced on Monday that it "successfully conducted one more underground nuclear test," demonstrating its "self- defensive nuclear deterrent" to the world. Both South Korea and Japan view a nuclear-armed DPRK the major threat to their security.

The DPRK staged its first nuclear test in October 2006.

U.S. President Barack Obama accused Pyongyang of "recklessly challenging the international community" with its new underground nuclear test.

"North Korea is directly and recklessly challenging the international community. North Korea's behavior increases tensions and undermines stability in Northeast Asia," he said.

"Such provocations will only serve to deepen North Korea's isolation. It will not find international acceptance unless it abandons its pursuit of weapons of mass destruction and their means of delivery," Obama said.

(Xinhua News Agency May 28, 2009)