While the UN was set up with the purpose of peacefully resolving all conflicts in the international community, this has not always been the case, underscored Pahor, noting that "the use of force in international relations remains a fact".

The president pointed to the UN as a vital instrument of keeping and preserving international peace, but admitted some felt ever stronger that the architecture of international community - particularly the US Security Council - is no longer able to adequately deliver due to the "changed historical circumstance".

Pahor therefore urged for a reform of the UN, saying the debate on this issue started several years ago but the necessary change had not yet been brought about. "This is way the peaceful part of the international community feels increasingly insecure about the peace in the future."

"If the UN fails to reform to be able to successfully help resolve international conflicts, these conflicts will increasingly start getting resolved without it," said Pahor, who will address the UN General Assembly on Friday.

Speaking at the Cerje memorial to those who defended Slovenian lands, Pahor described peace as "a value for which one should continuously make an effort and in whose spirit one should bring up young generations".

He urged for the annual ceremony near the city of Nova Gorica to grow into a recurring event at which peace would be promoted: "Peace is actually the most precious tribute to the victims of wars."

Every year, the UN secretary general's message about the International Day of Peace is read at the Cerje ceremony. The event is organised by the Miren-Kostanjevica municipality in cooperation with local patriotic associations of war veterans and their supporters.

The idea to build a memorial on Cerje was given in 1999 by TIGR, the patriotic organisation set in the 1920s to fight the Fascists in the western region of Primorsko. Having faced lack of money, the huge, three-storey monument was completed only in 2011.

The International Day of Peace, which was declared by the United Nations over three decades ago, and the Cerje ceremony coincide with the annual session of the UN General Assembly.