Belgium has become the latest Western nation to endorse Morocco's autonomy proposal as a solution for the decades-long Western Sahara dispute, according to a joint Moroccan-Belgian declaration signed Thursday.

The long-frozen conflict, dating back to 1975, pits Morocco, which considers the desert territory as its own, against the Algeria-backed Polisario Front, which seeks an independent state there.

Autonomy under Moroccan sovereignty "is the most adequate, serious, credible and realistic basis to reach a political solution" to the Western Sahara issue, Belgium said in the joint declaration signed in Brussels by Moroccan foreign minister Nasser Bourita and Belgian foreign minister and deputy prime minister Maxime Prevot.

Morocco's autonomy plan has the backing of the U.S., France and the UK within the U.N. Security Council.

Spain, the former colonial power in Western Sahara, has also backed Rabat's position, along with Germany and Portugal signaling a shift in EU member state foreign policy on the issue.

The EU, however, has not endorsed Morocco's autonomy propsal and continues to support U.N. efforts to reach a political solution to the conflict. Algeria and the Polisario denounced Western nations that back the autonomy plan and insist on holding a referendum with independence as an option.

The U.N. said the conflict was of low intensity and urged the parties to negotiate a mutually acceptable solution.