SEOUL: The leaders of the Republic of Korea (ROK) and the United States told the Democratic People's Republic of Korea (DPRK) to drop its atomic ambitions and stop threatening the region while media reports yesterday said Pyongyang was moving ahead with plans to launch a long-range missile.

After a summit with ROK President Lee Myung-bak in Washington on Tuesday, US President Barack Obama said a nuclear-armed DPRK would pose a "grave threat" to the world. He vowed new UN sanctions imposed for the DPRK's May 25 nuclear test would be strictly enforced.

Separately, the leaders of Russia and China called for speedy return to Six-Party Talks on the DPRK's nuclear program. Chinese President Hu Jintao and his Russian counterpart Dmitry Medvedev expressed serious concern over the situation on the Korean Peninsula, according to a joint statement issued at the end of talks in Moscow.