Moroccan police arrested at least 111 people who attempted to cross into Spain’s North African enclave of Ceuta, as authorities tightened security following calls on social media for another mass border crossing.

Axar.az reports, citing Reuters, that a source in Morocco’s Interior Ministry said those detained included 109 migrants from sub-Saharan Africa and two Moroccan nationals.

They were arrested in or around Fnideq, the Moroccan city opposite Ceuta.

Moroccan police used tear gas to disperse groups of migrants gathered on hills near the border. Authorities also increased security measures in northern Morocco, while Spain deployed additional police and military personnel in Ceuta.

Spanish Interior Minister Fernando Grande-Marlaska said authorities would continue strengthening security measures.

“We’ll continue to deploy whatever personnel are necessary to restore normality as soon as possible and prevent events like those of July 30 from happening again,” he said.

Moroccan authorities had warned earlier this week that they were monitoring social media posts calling for a mass crossing on August 15 and would prosecute organizers and participants.

The latest attempted crossing comes two weeks after more than 72,000 migrants entered Ceuta in a mass movement on July 30. At least 96 people died in the attempt to reach European territory.