Bush, speaking yesterday at the White House in Washington, described the Iranian government as refusing to negotiate over its nuclear program in "good faith."
"Obviously, we'd like to solve this issue peacefully and diplomatically, and the more the Iranians refuse to negotiate in good faith, the more countries are beginning to realize that we must continue to work together," Bush said.
Bush said the United States was working to make clear to Russia that Iran has not shown good faith.
Russia and China, both permanent members of the United Nations Security Council, have been reluctant to back western calls for tough measures against Iran, such as sanctions.
Bush, speaking at a joint news conference with Israeli Prime Minister Ehud Olmert, said his suspicions about Iran's nuclear intentions have been raised by Tehran's rejection of international offers to provide civilian nuclear material to Iran to ensure that the Islamic Republic will not develop atomic weapons.
Representatives of the United States, Russia, China, and the European Union trio of Germany, Britain, and France, are due to meet later today in London to discuss ways to persuade Iran to halt uranium enrichment work.
(compiled from agency reports)