Tadic, who won 50.57 percent of the vote against 47.71 percent for rival Tomislav Nikolic, promised during his inauguration to a second five-year term to preserve the country's sovereignty and territorial integrity, RIA Novosti reported Friday.

"I swear to devote all my strength to the preservation of the sovereignty and territorial integrity of the Republic of Serbia, including Kosovo and Metohija," Tadic said.

The president's statement comes as authorities in the province of Kosovo are preparing to declare independence Sunday from Serbia. However, the country has ruled out the use of military action to prevent the secession.

Serbia and Russia have expressed opposition to Kosovo's plans, while the United States and several European Union countries have voiced support for an independent Kosovo.