About 30 Kosovo Serbs are blocking a northern border crossing with Serbia in opposition to paying customs duties to ethnic Albanian authorities, which is part of an agreement reached between Serbia and Kosovo, the Associated Press reports.

The AP says its reporter at the Jarinje crossing on Saturday, Dec 14, saw passenger vehicles being allowed to pass but all trucks bringing goods into Kosovo were blocked.

In talks mediated by the European Union, Serbia agreed to allow Kosovo authorities collect customs in the Serb-dominated northern area. The deal that came into force on Saturday is overseen by EU customs officers, part of the bloc’s police and justice mission to Kosovo.

The funds are to be invested in the Serb-run north but many from the minority believe the deal effectively endorses Kosovo’s 2008 secession from Serbia.