Russian President Dmitry Medvedev and his U.S. counterpart Barack Obama on Monday have expressed hope here that their Moscow summit would yield tangible progress, Russian news agencies reported. 'It is certainly an important event in the history of Russian- American relations. We hope that we will close a number of complex pages in the history of Russian-American relations, and open a new page as a result of our work today and tomorrow and a full-scale exchange of views,' said Medvedev when opening talks with Obama, who arrived here on Monday afternoon. 'Our countries are encountering a variety of problems, including global security and strategic offensive weapons. I believe that we have every chance of taking important and necessary decisions,' said the Russian president. The two presidents will first hold talks in a narrow format, only with the participation of foreign policy advisers and foreign ministers. Then they will hold an enlarged-format talks with the participation of the two countries' delegations, said the Itar- Tass news agency. Obama hoped that their summit will be productive. Russia and the United States have more common approaches than disagreements concerning issues such as security, the economy, energy and the environment, said Obama. The U.S. president believed the two countries can achieve good results if hard- working efforts are made in the next few days, the Interfax news agency reported. Obama is on a three-day working visit to Moscow, the first one since he took office in January. The new treaty on nuclear arms cuts to replace the Strategic Arms Reduction Treaty (START I) that expires on Dec. 5 is expected to top their summit agenda. The two leaders are expected to sign as results of their talks a package of documents, including a framework document on START I, the transit of military and other cargos to Afghanistan, a joint statement on Afghanistan and a joint declaration on nuclear cooperation. Obama's visit to Moscow is widely anticipated as tone-setting for the development of Russian-U.S. relations in the future, analysts said. 