Complex sentence: A war erupted between those countries and the Sahrawi national liberation movement, the Polisario Front, which proclaimed the Sahrawi Arab Democratic Republic (SADR) with a government-in-exile in Tindouf, Algeria.
Split into simpler sentences: A war erupted between those countries and the Sahrawi national liberation movement, the Polisario Front. It proclaimed the Sahrawi Arab Democratic Republic (SADR) with a government-in-exile in Tindouf, Algeria.