Washington: Democratic presidential contender Barack Obama said today the United States should keep sanctions on North Korea until the Stalinist state proves unambiguously that its nuclear drive is over.

"The objective must be clear: the complete and verifiable elimination of North Korea s nuclear weapons programs, which only expanded while we refused to talk," Obama said in a statement.

President George W Bush today warily rewarded a new declaration from North Korea about its nuclear disclosures, easing trade sanctions and moving to take the "axis of evil" country off a US terrorism blacklist.

Obama said: "Sanctions are a critical part of our leverage to pressure North Korea to act. They should only be lifted based on North Korean performance.

"If the North Koreans do not meet their obligations, we should move quickly to re-impose sanctions that have been waived, and consider new restrictions going forward," the Illinois senator said.

"We should continue to pursue the kind of direct and aggressive diplomacy with North Korea that can yield results," he said, adding that answers were needed about nuclear proliferation to Syria and other nations.

Senator Obama noted that North Korea's declaration had not yet been made public, so Congress has yet to review it.

Source : PTI