Russian President Dmitry Medvedev expressed optimism Saturday about advancing relations with the U.S. during President Barack Obama's visit to Moscow in July even on divisive topics such as NATO's eastward expansion, news agencies reported, AP reported. Medvedev again criticized NATO's ongoing military exercises in Georgia, which Russia defeated in a brief war in August, saying such drills were clearly «provocative» and threatened stability in the region. He expressed hope, however, that he would have a fruitful discussion on security cooperation with Obama when he visits Moscow July 6-8. «I hope that in the course of our meeting we will be able to talk about these problems as well and give a new impulse to our contacts in this field,» Medvedev was quoted as saying by the RIA-Novosti news agency, after a meeting with Italian Premier Silvio Berlusconi. Medvedev has proposed to work out a new trans-Atlantic security pact between the U.S., Canada, the European Union, NATO and alliances of ex-Soviet nations. Obama has said that such a proposal is worth exploring _ part of the new U.S. administration push for better ties with Moscow. Russia and NATO recently started to improve ties frozen after Russia's war with Georgia in August, but tensions soared again over expulsions of diplomats and NATO exercises that began last week in Georgia.