Morocco stepped up measures Wednesday to prevent a fresh surge of migrants attempting to reach the Spanish enclave of Ceuta after authorities detected a new wave of online disinformation encouraging crossings.

For more than a week, online posts have claimed that the border crossing between the Moroccan town of Fnideq and the Spanish exclave would be open on Aug. 15, a public holiday in Spain.

It comes after around 72,000 people, mostly Moroccans, crossed into Ceuta irregularly over a few days in late July -- a record figure, though the vast majority of them have since been returned to Morocco.

"All the necessary measures were taken to counter all attempts at illegal passage and intercept every person seeking to participate," Moroccan interior ministry spokesman Rachid El Khalfi said.

The ministry said it "detected over the last days the circulation of publications and anonymous messages on social media inciting the organisation of collective, illegal crossing attempts" towards Ceuta.

Legal proceedings would be taken against those spreading the calls, it added.

A group of individuals suspected of being involved has been summoned for investigation, El Khalfi added in remarks carried by the state news agency MAP.

Following the migrant influx last month, some 2,000 people including about 1,000 unaccompanied minors remain in the Spanish territory, according to local authorities there.

The Moroccan interior ministry has urged Spanish authorities to speed up the return of the minors.

Moroccan authorities recovered 11 dead people in the wake of the crisis, while Spain said at least 80 people died.

But the Moroccan Association for Human Rights, a non-governmental group, estimated the death toll to be at least 141.