MADRID (AP) — Desperate to reach Europe from North Africa, two African migrants were discovered by police attempting to cross the Spanish border hidden inside a pair of mattresses.

A video shot by a mobile phone of the move Sunday went viral in Spain. It showed agents of Spain's Civil Guard taking two mattresses off the top of a van and cutting them open to reveal two young men inside.

The Civil Guard told The Associated Press on Tuesday the incident occurred at a border crossing from Morocco to Melilla, one of two Spanish cities on the North African coast.

The two migrants told the police they each paid 4,500 euros ($5,100) to a human trafficker to attempt the crossing. The driver of the van fled on foot when agents asked to inspect his cargo. The two men were taken to a migrant holding center.

Also Tuesday, Spain's maritime rescue service said its craft saved 111 migrants trying to cross the Strait of Gibraltar or nearby waters.

Over 2,200 migrants died trying to reach Europe across the Mediterranean Sea in 2018, according to the U.N. Refugee Agency.

Following crackdowns on immigration by Italy and other countries, Spain has become the preferred route to Europe for migrants and their traffickers, who often pack them into boats unfit for open waters.

The U.N. said over 62,000 migrants arrived in Spain in 2018 after making the dangerous trip across the Mediterranean, while another 6,723 came over land. Melilla itself received over 5,000 migrants in 2018.