Eighteen Africans seeking to cross into Spain were killed and scores of migrants and police were injured in what Moroccan authorities called a “stampede” of people surging across Morocco’s border fence with the Spanish North African enclave of Melilla on Friday.

A total of 133 migrants breached the border between the Moroccan city of Nador and Melilla on Friday, the first such mass crossing since Spain and Morocco mended diplomatic relations last month. A spokesperson for the Spanish government’s office in Melilla said about 2,000 people attempted to cross, but many were stopped by Spanish Civil Guard police and Moroccan forces on either side of the border fence.

Morocco’s Interior Ministry said in a statement that the casualties occurred when people tried to climb the iron fence. It said five migrants were killed and 76 injured, and 140 Moroccan security officers were injured.

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Thirteen of the injured migrants later died in the hospital, raising the death toll to 18, according to Morocco’s official news agency MAP., which cited local authorities. The Moroccan Human Rights Association reported 27 dead but the figure could immediately be confirmed.

Spanish officials said 49 Civil Guards sustained minor injuries. Four police vehicles were damaged by rocks thrown by some migrants.

Those who succeeded in crossing went to a local migrant center, where authorities were evaluating their circumstances.

People fleeing poverty and violence sometimes make mass attempts to reach Melilla and the other Spanish territory on the North African coast, Ceuta, as a springboard to continental Europe.

Spain normally relies on Morocco to keep migrants away from the border.

Over two days at the beginning of March, more than 3,500 people tried to scale the six-meter (20-foot) barrier that surrounds Melilla and nearly 1,000 made it across, according to Spanish authorities.

Friday’s crossings were the first attempt since relations between Spain and Morocco improved in March after a year-long dispute centered on the Western Sahara, a former Spanish colony annexed by Morocco in 1976.

Morocco loosened its controls around Ceuta last year, allowing thousands of migrants to cross into Spain. The move was viewed as retaliation for Spain’s decision to allow the leader of Western Sahara’s pro-independence movement to be treated for COVID-19 at a Spanish hospital.

Tensions between the two countries began to thaw earlier this year after Spain backed Morocco’s plan to grant more autonomy to Western Sahara, where activists are seeking full independence