Morocco has accused U.N. Secretary-General Ban Ki-moon of "abandoning neutrality, objectivity and impartiality" during a recent visit to Western Saharan refugee camps in southern Algeria.

Morocco's Foreign Ministry has criticized Ban's trip in a statement, condemning the use of the term "occupation" in describing the territorial status of the Western Sahara.

The United Nations issued a response late Wednesday, saying Ban referred to the "occupation" of the territory because of "the inability of Sahrawi refugees to return home under conditions that include satisfactory governance arrangements under which all Sahrawis can freely express their desires."

During his weekend visit, Ban expressed frustration over dire living conditions in the camps and called for renewed peace talks for the Western Sahara, annexed by Morocco in 1975.

Ban has announced plans for a donors' conference to address the Morocco situation.

Morocco expressed "regret" over the plans to organize the donor's conference, and said past international aid has been unfairly spent. The government statement Tuesday also questioned why the U.N. chief didn't address concerns about rights violations in the Tindouf camps.

Ban also visited Algiers over the weekend, where he stated that there was "no real progress" in reaching a solution for the Western Sahara conflict.

While Ban's tour didn't take him to Morocco, the U.N. indicated there are plans for him to visit Morocco in the near future.

Morocco has proposed wide-ranging autonomy for the mineral-rich Western Sahara, but the Polisario Front insists on self-determination for the local population through a referendum.

The Polisario Front is seeking independence for the territory and currently controls the Tindouf refugee camps in southern Algeria. U.N. peacekeepers are monitoring a cease-fire brokered in 1991.