U.S. Defense Secretary Ashton Carter on Saturday stressed the need to maintain the current multilateral and diplomatic approach to persuade North Korea to give up its nuclear ambitions.

"North Korea remains a troubling and provocative exception to the general rule in this (Asia-Pacific) region of countries that pursue systems of peace and stability," Carter said in his speech delivered at the Asia Security Summit, better known as the Shangri-La Dialogue, in Singapore.

Five members of the six-party talks aimed at denuclearizing the North -- the U.S., South Korea, Japan, China and Russia -- "have attempted collectively with a multilateral, diplomatic approach to stop it," which is "creating an environment of the Korean Peninsula that is nuclear weapons free," the secretary said.

While admitting that their effort has not yet been successful, Carter pointed out that it has shown "great solidarity" among the five countries united in the opposition to the nuclear proliferation."

The six-party forum, also involving North Korea, has been dormant since late 2008.

Refuting the criticism of the Obama administration's so-called strategic patience with the bellicose regime, he said the collective security system in Asia "has been enormously successful" over the past decades.

He, however, refused to elaborate on the suspected nuclear connection between Iran and North Korea. (Yonhap)