Hundreds of immigrants have tried to break through the border fences around the Spanish enclave of Melilla in North Africa, police sources say.
Immigrants have used home-made ladders to scale the fences (Image: Melilla Hoy)
At least 18 people - both police and immigrants - were injured.
About 100 people managed to break through into Spanish territory, where they are being questioned.
Melilla and nearby Ceuta are seen as stepping stones to Europe by African immigrants. Spain is doubling the height of the fences around Melilla.
Three immigrants have died since August trying to enter Melilla.
Many migrants are caught and many drown while attempting to make the sea crossing to Spain - either across the Mediterranean Sea or to the Canary Islands, over the Atlantic Ocean.
A Guardia Civil spokesman said groups had been trying to cross where the perimeter fencing remains 3m high.
It is at these points where work is being carried out to double the height.
Police found more than 200 makeshift ladders.
Moroccan police were also called and detained 50 African immigrants.
Spanish guards on the borders have responded to the attempted invasions with anti-riot methods.
The Doctors Without Borders (MSF) charity criticised what it called "the violence" used by the Spanish and Moroccan security forces.
In the past week, the Moroccan authorities have arrested more than 1,000 people planning to travel illegally to Europe.
Some 300 were Moroccan, the others from sub-Saharan Africa.