The president of South Korea says his country and Russia are both worried about North Korea's moves to restart its nuclear program. South Korean President Lee Myung-bak made the statement Monday after meeting Russian President Dmitry Medvedev for talks at the Kremlin. Russia belongs to the six-nation group negotiating to convince North Korea to dismantle its nuclear program in return for diplomatic concessions and aid. North Korea ordered UN monitors last week to leave the country and said it would reinsert nuclear material into a plutonium-producing facility. The two leaders also oversaw the signing of several deals Medvedev said will bring Moscow's relations with Seoul to the level of "strategic partnership."