Mauritania has passed a law promising jail time for slave-holders, an important step in the northwest African country's push to eliminate a practice that has quietly persisted despite a 25-year-old ban.

The law, adopted unanimously late Wednesday by the legislature, calls for prison sentences of up to 10 years for people found keeping slaves, along with fines for slave-holders and reparations for those who have been enslaved.

Human rights campaigners praised the law as a signal that a long-awaited cultural shift might finally be taking hold in Mauritania, where slavery has existed for hundreds of years and is ensconced in traditional proverbs, songs and poems. The new law prohibits many of these as pro-slavery propaganda.