He also described the issue as the “clear and simple measure for the sincerity of friendships” between Morocco and its partners, in remarks marking the Revolution of the King and the People, a national holiday that celebrates the kingdom’s anti-colonial struggle.
Rabat controls most of Western Sahara, which it views as its own territory.
Morocco fought a 15-year war with the Polisario Front independence movement after Spain withdrew from its former colony in 1975.
A United Nations-monitored ceasefire deal provided for a referendum, but Morocco has since rejected any vote that includes independence as an option, offering only limited autonomy.
King Mohammed VI called on allies to “clarify their stance… in an unequivocal manner” on the matter. He did not specify which countries he was addressing, but saluted the United States’ “incontrovertible” position.
The US under former president Donald Trump recognized Morocco’s sovereignty over the disputed former Spanish colony, a policy that has continued under his successor Joe Biden.
The king also lauded recent moves by Spain and Germany to reverse previous policies and recognize Rabat’s autonomy initiative for the territory.
In a U-turn, Spain in March publicly backed Morocco’s autonomy plan for the disputed region after a months-long diplomatic spat.
Rabat and Berlin had in February agreed to renew ties after a year-long diplomatic freeze over disagreements including on Trump’s recognition of Moroccan sovereignty over the Western Sahara.