In an exclusive interview with Xinhua, Eberhard Sandschneider, head of the German Council on Foreign Relations (DGAP), said sanctions would "not have any major impact" on the DPRK and would not help persuade the country to give up its plan to seek nuclear weapons.

"You can never force a country that won't cooperate...," said the German expert, adding that this rule also applied to Iran.

Sanctions would not work on countries such as the DPRK, he said.

Other forms of pressure were also unlikely to bring about any positive results even if backed by military threats, said Sandschneider, adding that military strikes against the DPRK were unlikely to happen as the United States was already over-stretched in Iraq.

The only way to solve the nuclear crisis was to remain in "credible talks without any preconditions," and such talks should be initiated by the United States, which the DPRK considered as its major threat, he said.

The DPRK was seeking nuclear weapons largely to prevent sanctions or strikes from the United States, he said.

Meanwhile, Sandschneider warned of the danger of a potential arms race in Asia, as the DPRK's nuclear test could push the non-nuclear Asian countries such as Japan, to develop nuclear weapons.

The DPRK's official Korean Central News Agency said on Monday morning that the country had successfully conducted its first-ever underground nuclear test.