One African migrant died and three others were injured when around 300 stormed the border fence separating Spanish enclave Melilla from Morocco in north Africa on Sunday.
About 200 migrants managed to scale the seven-metre high metal barrier.
The border is protected by two fences toped with barbed wire.
They were taken to a reception centre where officials started the process of identifying them. The man died of a suspected cardiac arrest.
More than 6,000 migrants have made it to Melilla and Spain’s nearby territory Ceuta so far this year, according to the UN refugee agency UNHCR.
More than 40,000 have arrived by sea on Spain’s southern coast since January.
The routes have changed as Italy clamped down on rescue ships trying to dock at its ports.
But although the Labour-type Spanish government has not followed the Italian government’s lead, it is expelling migrants.
Last Saturday Spain returned 24 migrants to Morocco who reached the Chafarinas islands, another Spanish territory off the North African coast.
The fate of thousands of others is unclear.
The islands’ royals live in luxury
Workers’ are fighting back for better pay and conditions