Madrid (dpa) - African would-be immigrants travelling to Spain by boat attacked a Spanish police vessel with petrol bombs, preventing the officers on board from detaining them, the daily El Pais reported Tuesday.
The boat was taking 57 migrants from Mauritania in West Africa to the Canary Islands, when a Spanish patrol boat based in Mauritania attempted to intercept it.
The immigrants hurled petrol bombs and other objects at the vessel and tried to puncture a rubber dinghy which was sent to accost it.
Police decided to allow the boat to continue its journey, because its movements were endangering the lives of its occupants, according to the report.
However, police alerted the European frontier agency Frontex, which sent an aeroplane to follow the boat until it reached Gran Canaria Island.
The attackers were to be sent back to Mauritania, which intended to try them for an attack in its territorial waters.
The attack was highly unusual in the history of immigration to Spain, which receives tens of thousands of African illegals annually.