Russian President Dmitry Medvedev has arrived in Serbia, bringing a $1-billion loan to the recession-hit country as Moscow seeks to expand its influence in the Balkans, AP reported. The loan deal is to be signed during Medvedev"s one-day visit _ the first-ever by a Russian president to Serbia. The loan adds to Russia"s growing political and economic clout in Serbia, which relies on Moscow"s diplomatic support in the U.N. Security Council to oppose the secession Kosovo, Serbia"s former province. Thousands of policemen were deployed on Belgrade streets on Tuesday and much of the Serbian capital was blocked for traffic amid tightened security for the visit. --SPA