The possibility of a third nuclear test or long-range missile launch by North Korea is a likely discussion topic for the presidents of South Korea and the United States next week, after a presidential aide warned Friday that the North is ready for further testing if six-party talks do not resume. Kim Tae-hyo, deputy national security advisor to President Lee Myung-bak, said Lee and U.S. President Barack Obama will hold \"in-depth\" discussions about the allies\' \"conventional and extended nuclear deterrence\" during next week\'s summit in Washington. \"I think that North Korea could test-launch a long-range missile or conduct a third nuclear test if denuclearization talks with South Korea and the U.S. fail,\" Kim told a security forum in Seoul. In particular, North Korea is likely to instigate \"provocative actions\" if Pyongyang judges it can\'t receive economic assistance from South Korea and the U.S. ahead of next year\'s presidential elections in both nations, Kim said. Kim did not state whether he had information to suggest preparations for a nuclear test in North Korea were underway. Tensions have persisted on the Korean Peninsula over the North\'s sinking of a South Korean warship in March last year and the shelling of a South Korean border island in November. Pyongyang has refused to take responsibility for the two deadly attacks that killed 50 South Koreans. After sharply raising tensions, North Korea called for an unconditional resumption of the six-nation talks, which have been stalled since late 2008. The talks, involving the two Koreas, the U.S., Russia, China and Japan, are aimed at persuading North Korea to give up its nuclear weapons programs in return for economic aid and diplomatic recognition. Since July, South Korea and the U.S. have held preliminary talks with North Korea to discuss preconditions for resuming the six-party talks, but no tangible progress has been made. Seoul and Washington have urged Pyongyang to demonstrate its sincerity toward the six-party talks through action, mindful of the North\'s typical pattern of raising tension with provocations and then calling for dialogue to extract further concessions. The North previously conducted nuclear tests in 2006 and 2009, drawing harsh international condemnation and sanctions.