Spanish Prime Minister Pedro Sanchez described Morocco's actions during a crisis two weeks ago when thousands of would-be migrants crossed into Spain's north African enclave of Ceuta as unacceptable and an assault on national borders.
Asked at a news conference on Monday (May 31) about comments by the Moroccan foreign minister, who linked the migrant crisis to the disputed territory of Western Sahara, Sanchez said:
"It is not acceptable for a government to say that we will attack the borders, in this case the Spanish border, to open up the borders to let in 10,000 migrants in less than 48 hours in a Spanish city like Ceuta because of foreign policy disagreements."
Two weeks ago, thousands of people swam around the border or scaled the fence separating Ceuta from Morocco over two days after Moroccan security forces appeared to loosen border controls.
Most were immediately returned to Morocco but hundreds of unaccompanied minors, who cannot be deported under Spanish law, remain.
The influx was widely seen as retaliation for Spain's decision to take in Brahim Ghali, head of the Western Sahara Polisario independence group, for medical treatment.
For decades, Polisario has fought for independence for the territory, where Spain was colonial ruler until 1975.
Describing Spain as Morocco's best ally in the European Union, Sanchez said he wanted to convey a constructive attitude towards Rabat but insisted that border security was paramount.