Obama, McCain Cautious on NKorea Declaration

John McCain was equally cautious, although he said that `obviously the six party talks have yielded some results here.`

U.S. Democratic presidential candidate Barack Obama said on Thursday that critical questions remained unanswered in North Korea's nuclear declaration and it was crucial for Congress to review it.

Obama, a senator from Illinois, said in a statement that U.S. sanctions on Pyongyang should only be lifted "based on North Korean performance." The declaration was a step forward but other steps needed to follow, he said.

"Before weighing in on North Korea's removal from the list of state sponsors of terrorism, Congress must take the next 45 days to examine the adequacy of the North Korean declaration and verification procedures," he said. "Sanctions are a critical part of our leverage to pressure North Korea to act."

Obama has drawn criticism from some opponents for advocating more direct talks with countries hostile to the United States including Iran, which, like North Korea, is under U.S. sanctions over its nuclear program.

Obama's Republican opponent in the November U.S. presidential election, John McCain, was equally cautious, although he said that "obviously the six party talks have yielded some results here."

"We'll have to have a look and see how the overall agreement is and whether we should continue to lift sanctions, whether the Japanese and South Korean concerns have been addressed," the Arizona senator told reporters in Cincinnati.