"We believe that Serbia is a unified state, whose jurisdiction extends over its whole territory, and we will maintain this position in the future," Medvedev said at the talks with Serbian Prime Minister Vojislav Kostunica in Belgrade.
The Kosovo parliament unilaterally adopted on February 17 a declaration on the breakaway republic's independence from Serbia. Belgrade has called the decision illegal and is demanding to cancel it. The United States and some other Western countries have recognized Kosovo's independence.
Medvedev, who is the Kremlin's front-runner in the upcoming presidential elections, said the unilateral declaration of independence by Kosovo had undermined the situation in the Balkans and the whole Europe.
"To a larger extent, the negative consequences of this precedent are spreading over other regions and states, where the issue of territorial integrity has become a matter of concern," Medvedev said.
Protests against Kosovo's independence, the largest in Serbia's history, turned into street riots in Belgrade last week leaving at least 130 people injured and 192 rioters arrested.
Rioters attacked the embassies of the United States, Croatia, Belgium and Turkey, throwing stones and Molotov cocktails.
Police used tear gas to disperse the crowd. Hustled away from the embassies, the rioters - mostly young people - moved down the streets looting and damaging at least 90 shops, kiosks and setting cars on fire.
Washington and the UN Security Council condemned the attacks on the U.S. Embassy in Belgrade and urged Serbs to stay within international law and to respect the status of diplomatic missions. The EU followed suit.
Medvedev said at a joint news conference with the Serbian premier on Monday that Russia and Serbia would coordinate their efforts to resolve the current political crisis over Kosovo's independence.
"This coordination will be maintained in the framework of all interested bodies and organizations," he said.
Vojislav Kostunica echoed Medvedev's statements by saying: "We will fight together with Russia and will demand the annulment of these illegal decisions [announcement of Kosovo's independence]."
He added that the Russian and Serbian position on Kosovo issue was supported by some other countries that "keep the respect toward the fundamental principles of international law close to their hearts."
The U.S., Australia, and several leading European countries, including France, Italy and Germany, have so far recognized Kosovo as an independent country, while Russia, Serbia, China and Spain have condemned the independence move.