Spanish and Moroccan human rights groups have called for an inquiry after more than 20 migrants died when around 2,000 people tried to cross the border.
The number of people who were killed after they tried to scale a border fence between Morocco and a Spanish enclave in North Africa rose to 23 at the weekend.
Human rights organisations in Spain and Morocco called on both countries to investigate the circumstances surrounding the deaths.
Moroccan authorities said the individuals died as a result of a “stampede” of people who attempted Friday to climb the iron fence that separates the city of Melilla and Morocco.
The ministry initially reported five deaths before the tally rose progressively. Morocco’s Interior Ministry said 76 civilians were injured along with 140 Moroccan security officers.
Spanish authorities say around 2,000 people attempted to breach the border, and at least 133 migrants were successful.
It is the first mass crossing attempt since Spain and Morocco mended diplomatic relations last month.
Authorities had been anticipating a mass crossing attempt in recent days after hundreds of sub-Saharan migrants gathered in the mountainous region.
Many migrants were stopped by Spanish Civil Guard police and Moroccan forces on the other side of a border fence on Friday morning. Those who succeeded in crossing were taken to a local migrant centre to evaluate their circumstances.
Spanish Prime Minister Pedro Sánchez on Saturday condemned what he described as a “violent assault” and an “attack on the territorial integrity” of Spain. Spanish officials said 49 Civil Guards sustained minor injuries.
His remarks came as the Moroccan Human Rights Association shared videos on social media that appeared to show dozens of migrants lying on the ground, many of them motionless and a few bleeding, as Moroccan security forces stood over them.
“They were left there without help for hours, which increased the number of deaths,” the human rights group said on Twitter. It called for a “comprehensive” investigation.
Spain normally relies on Morocco to enforce the border to deter migrants from reaching Europe.
Over two days in March, more than 3,500 people tried to scale the six-metre-high barrier that surrounds Melilla. Nearly 1,000 successfully crossed into the North African city, according to Spanish authorities.
Last year, Morocco had loosened its controls around Ceuta, another Spanish enclave, as tensions heightened between the two countries.
The move was viewed as retaliation after Spain allowed the leader of Western Sahara’s pro-independence movement to be treated for COVID-19 at a Spanish hospital.
But relations improved this year when Spain backed Morocco’s plan to grant more autonomy to Western Sahara, a former Spanish colony annexed by Morocco in 1976.