The leader of Western Sahara's independence movement, will appear before a Spanish court Tuesday to answer allegations of torture and genocide.
The hearing comes amid heightened tensions between Rabat and Madrid over Ghali's presence in Spain.
Brahim Ghali's treatment for COVID-19 at a hospital in Spain since mid- April has soured relations between Madrid and Rabat.
Ghali heads the Polisario Front , a group which is based in southern Algeria and fights for independence of the Western Sahara, which Morocco annexed in the 1970s.
With Ghali considered a "war criminal" by Rabat, the Moroccan government last week decided to turn a blind eye at its shared border with the Spanish enclave of Ceuta, and allowed thousands of immigrants access to the enclave, much to the anger of Spain's Prime Minister Pedro Sanchez.
"It is unacceptable for a government to say that it is attacking the borders, in this case Spain's borders, that it is opening the borders so that 10,000 immigrants can enter a Spanish city such as Ceuta in less than 48 hours because of disagreements and differences, discrepancies in foreign policy." says Pedro Sanchez, Spanish Prime minister.
Madrid agreed to treat Ghali as a favour to Algeria, its main supplier of natural gaz - according to El Pais.