Xi's three-day visit, his first foreign trip since he became president, began Friday, RIA Novosti reported. He spent seven hours with Prime Minister Vladimir Putin and signed a number of trade agreements.
"From my point of view, my visit has already reached its aim. The results have far exceeded my expectations," Xi told Medvedev.
Xi also addressed students Saturday at the Moscow Institute of International Relations.
"Russia and China should strengthen strategic cooperation on the international scene, together defend the U.N. principle regulations and secure peace and stability," Xi said.
The two countries are frequent allies on the U.N. Security Council.
One of the agreements signed Friday was a tentative pact between the Russian state company Gazprom and the China National Petroleum Corp. It would guarantee annual supplies of natural gas to China.