Russia will insist on a diplomatic solution to the Iranian nuclear crisis when diplomats from six countries involved in searching for a resolution meet in Moscow this week, the Russian Foreign Ministry said Monday. "We proceed from the assumption that the Iranian nuclear problem should be solved through diplomacy," ministry spokesman Andrei Krivtsov told The Associated Press. "This opinion is invariable and it will be reaffirmed at the upcoming talks." The United States and Britain say that if Iran does not comply with the UN Security Council's demand to stop uranium enrichment by April 28, they will seek a resolution that would make the demand compulsory. Enrichment can produce fuel for a nuclear reactor or material for a bomb. Political directors of the foreign ministries of Russia, the United States, China, Germany, France and Britain will meet over dinner Tuesday to discuss Iran, a Western diplomat said on customary condition of anonymity. Discussions of the Iranian crisis are to continue during a Wednesday meeting of envoys from the Group of Eight major industrialized nations, the Western diplomat said.