Thousands of Spanish and Moroccan security officers reinforced Ceuta’s borders on Friday as online messages spread calling for a new mass incursion into the exclave in North Africa.

Following last month’s unprecedented arrival of 72,000 migrants into the Spanish city, viral social media posts proposed a similar surge be staged on Saturday, Aug. 15 — a national holiday in Spain. Authorities in Madrid and Rabat have been tracking the online chatter and coordinating a common response.

Moroccan Interior Ministry Spokesperson Rachid El Khalfi on Wednesday confirmed the country was “taking all necessary measures to counter any attempt at illegal crossing,” and local journalists reported a significant buildup of troops around the border town of Fnideq on Friday.