RABAT, Morocco – On his deathbed, the head of a major West African separatist group stunned doctors and colleagues by repudiating his nearly half-century alliance with Algeria, according to a Madrid-based news site.

Mohamed Abdelaziz, whose Polisario Front has opposed the Moroccan presence in the Western Sahara since the 1970s, died Tuesday of lung cancer at the Mayo Clinic in Rochester, Minnesota. Abdelaziz, president of the Sahrawi Arab Democratic Republic, had been a daily smoker for most of his life.

Before he died, Abdelaziz confided to close associates that he had realized his own beliefs had become "obsolete" and the long-simmering conflict in the region was pointless, according to the Spanish-language news site lainformacion.com.

The dying leader also regretted his alliance with Algeria and felt guilty over the conflict, according to the site.

Algeria sheltered and supported the rebel Polisario Front for decades as part of a proxy war against the neighboring kingdom of Morocco. Abdelaziz's regrets, if true, would be a stunning turnaround for the movement and its supporters.

In a spokesman's statement on Tuesday, U.N. Secretary-General Ban Ki-moon offered "condolences to Mr. Abdelaziz's family and to the Frente Polisario as they mourn his untimely loss."

Ban made the V sign while with Polisario Front supporters during a visit to a refugee camp in March, and was reported to have called Morocco's 1975 annexation of portions of Western Sahara an "occupation."

Tuesday's statement said Ban looked forward "to continuing to work to help the parties to achieve a mutually acceptable political solution, which will provide for the self-determination of the people of Western Sahara."

The territorial dispute over what is now the southern half of Morocco – which some Sahrawi tribes claim as their homeland and seek to establish as an independent state – is one of the longest-running and thorniest diplomatic issues in the world today. Algeria supported the creation of a new, independent state that would have been ruled by Abdelaziz, while Morocco instead offered regional autonomy and economic development.

Abdelaziz spent most of his life in the Sahrawi refugee camps near Tindouf, Algeria – a collection of concrete and mud-brick huts scattered among the stony outcroppings in the Sahara Desert – alongside the thousands of Sahrawi refugees he represented. He ruled over some 100,000 followers in a one-party state that barred alternative political parties.

Algeria provided weapons, tanks, food, passports and millions of dollars to the Polisario Front over the last four decades. Earlier this year, Abdelaziz received a written note from Algerian President Abdelaziz Bouteflika on the 40th anniversary of the proclamation of the SADR.

"Algeria will spare no effort to provide support to the U.N. secretary-general's proposal to revive direct negotiations between Morocco and the Polisario," Bouteflika wrote.

Abdelaziz waged a guerilla war against Morocco under the militant banner of the Polisario Front from 1976 until a U.N.-brokered cease-fire agreement took effect in 1991. His followers called that bloody period "the years of lead." Since then, the U.N. Mission for the Referendum in Western Sahara has monitored the cease-fire and maintains a buffer between Morocco and the Algerian-backed separatist movement.

Abdelaziz was reportedly born in Marrakesh, Morocco, though some Sahrawi tribal leaders maintain that he was born in 1948 in Smara, a village deep in arid Western Sahara lands.

The separatist leader had family ties to Morocco. Abdelaziz's father, Khalili Ben Mohamed Al-Bachir Rguibi, was a member of the Royal Moroccan Army and active in the Royal Advisory Council for Saharan Affairs.