Migrants swim through the waters close to the border with Morocco to enter Spain's north Africa's Ceuta enclave on July 31. Thousands of migrants crossed overnight from Morocco into Ceuta enclave, a police source said, as Spanish Prime Minister was set to arrive to manage the latest migrant crisis on the border. In recent days, a total of around 40,000 migrants have crossed into the territory, population 80,000, the source added. AFP-Yonhap

CEUTA, Spain — At least 18 migrants have died trying to reach the Spanish territory of Ceuta after thousands of people breached the frontier with Morocco and poured in.

The border crisis boiled over Thursday and continued on Friday ahead of Spain's Prime Minister's visit to the exclave, with security forces clashing with migrants on the Moroccan side of the border.

Live footage of the border showed hundreds of migrants gathered on a hill overlooking Ceuta being dispersed with tear gas by Moroccan forces, while others continued to swim to the Spanish territory.

At the same time, large groups of migrants walked back from Ceuta toward Morocco to return home.