[HIGHLIGHTS] Serbia puts its forces on high combat alert and orders army units to approach the border with Kosovo

Kosovo has been at odds with Serbia since the 1990s. The two countries are at odds over Kosovo's membership in the European Union.

The dispute is over the right of Kosovo's citizens to vote in European elections. The EU has refused to recognise Kosovo's right to vote for the first time since 1998. The European Union has also refused to recognize Kosovo's status as a member of the EU, citing human rights concerns. The U.S. government has said it will not recognize Kosovo as an EU member state unless the EU recognises Kosovo's sovereignty.