Morocco: What triggered the mass migrant crossings into the Spain's Ceuta?

Over the last 24 hours, the tiny Spanish territory of Ceuta - home to around 83,000 people - has seen an unprecedented surge in migrant arrivals.

An estimated 60,000 people from Morocco are believed to have crossed into the North African enclave that has long been a focal point for migrant attempting to reach Europe.

Dozens of people died while trying to make the crossing.

On Friday evening, Spanish officials confirmed that more than 48,000 of the migrants had voluntarily returned to Morocco.

BBC's Sarah Rainsford explains what may have triggered the surge in crossings and what happens next.

More on this story: How Spain's migrant crisis created a political storm - whipped up by social media

Reporting from BBC News contributed to this story.