BELGRADE, Nov. 4 (Xinhua) -- Slovenia's coalition parties welcomed the signing of an arbitration agreement with Croatia concerning border issues on Wednesday.

    But the opposition labeled the action a betrayal of Slovenia's national interests and called for a referendum on the issue.

    Slovenian Prime Minister Borut Pahor and his Croatian counterpart Jadranka Kosor signed the agreement in Stockholm.

    The measure provides for the establishment of an international arbitration tribunal to determine the course of the border at sea and on land, Slovenia's contact with the high seas, and the use of relevant maritime areas.

    Pahor's party, the Social Democrats (SD), said in a press release that it was a "historic act in the relations between Slovenia and Croatia" and the biggest diplomatic achievement of the two countries in recent time, according to Slovenian state news agency STA.

    The head of the junior coalition Liberal Democrats (LDS) Katarina Kresal said all ministers of the government were behind Pahor and "support the direction in which this negotiations went."

    The leader of the hard line opposition National Party (SNS), Zmago Jelincic, however, said "Mr. Pahor has betrayed Slovenia." and announced that the SNS, together with another two opposition parties, would file a motion for a referendum.

    The arbitration agreement was a condition Slovenia had set for unblocking Croatia's membership talks with the EU.