The arms found include rockets and ammunition.
A police statement said the joint raid by police and NATO peacekeepers was conducted on December 20 at a house in central Kosovo's Drenica region.
The seizure comes as United Nations-mediated negotiations are under way to resolve the future status of the predominantly Albanian-populated Serbian province. Kosovo has been administered by the UN since 1999.
Reports quoting local officials said one of the two arrested members of the Alliance for the Future of Kosovo is a government adviser.
(AP, Reuters, AFP)