A U.S. State Department official on Monday urged Kosovo to end taxes on Serbian goods so that European Union-mediated talks on resolving the dispute between the former war foes could resume, reports AP.

Deputy Assistant Secretary of State Matthew Palmer said at a joint press conference with Serbian President Aleksandar Vucic that full normalization of relations between Serbia and its former province is “essential” for the future of Western Balkans.

Palmer said the tariffs present an “obstacle” for the dialogue and should be “lifted or suspended”.

Kosovo officials have repeatedly rejected calls by U.S. and EU officials for the lifting of taxes.

Serbia, which has the support of Russia, wants a compromise agreement with Kosovo. Kosovo, supported by the U.S., insists on full recognition of its statehood as the end result of the talks.

The Serbian president said he told Palmer that only a solution that takes into account the interests of both Kosovo Albanians and Serbs could end the long-standing dispute.