SEOUL — Despite their frequent meetings, Prime Minister Taro Aso and South Korean President Lee Myung Bak have produced no substantial results on issues linked to North Korea, dashing hopes that the two leaders may achieve a breakthrough in the deadlock on the Korean Peninsula.

Since taking office last September, Aso has met Lee five times, including Monday's summit in Seoul, at which the two leaders only agreed on the need to continue efforts under the six-party framework and trilaterally with the United States to denuclearize North Korea and resolve the issue of Japanese abductees.

Political pundits and observers said the leaders, who are often described as tougher on Pyongyang than their predecessors, are unable to engage in full-fledged talks on regional issues as they struggle to deal with domestic problems. These include the stalemate in Diet deliberations in Japan and recessions in both countries that have resulted in mass layoffs. Both Aso and Lee are also plagued by public doubts about their leadership abilities.