BRUSSELS, June 2 (Xinhua) -- NATO Secretary General Jaap de Hoop Scheffer said on Monday he is deeply concerned over international observers' conclusions that Macedonia elections on Sunday did not meet key international standards.

    The Organization for Security and Cooperation in Europe (OSCE) Observer Mission said in its preliminary conclusions that Macedonian election day was marred by violent incidents, intimidation and ballot stuffing in predominantly ethnic areas.

    "Countries working toward NATO membership must make every effort to meet the democratic standards of the alliance," said de Hoop Scheffer in a statement.

    Macedonia failed to get invitation for membership at the April NATO summit in Romanian capital Bucharest due to its long-standing name dispute with Greece.

    Greece insists that the constitutional name of Macedonia - the Republic of Macedonia -- implies Skopje's territorial ambitions for the northern Greek province which is also called Macedonia.

    NATO heads of state and government promised to issue an invitation for membership talks once the name issue has been resolved.

    De Hoop Scheffer asked Macedonia to take active steps to address the security and electoral shortfalls. He said NATO will carefully assess the OSCE Observer Mission's final conclusions.

    He stopped short of saying whether Macedonia's elections, if proven sub-standard by the OSCE mission, would affect the current roadmap of the country's NATO membership.