An Italian prosecutor has ordered the seizure of the Spanish rescue ship Open Arms and the evacuation of the more than 80 migrants still on board, according to reports.

The move caps a dramatic day that saw some 15 migrants jump in the sea to escape the ship after being frustrated and angry at the 19 days they were stuck at sea.

With the help of Italian rescue workers, those swimmers reached the shores of the nearby Italian island of Lampedusa.

Europe Migrants
Prosecutor Luigi Patronaggio (Salvatore Cavalli/AP)

But Open Arms said that made operations on board “desperate” and “intolerable” for the remaining migrants.

Spain tried to end the spiralling humanitarian crisis by dispatching a naval ship to escort the Open Arms back to Spain.

News agency ANSA said Sicilian Prosecutor Luigi Patronaggio ordered the seizure after visiting the ship and meeting with port authorities.

Mr Patronaggio is investigating possible charges of kidnapping against Italy’s hard-line interior minister, Matteo Salvini, who has refused to allow the migrants on shore despite offers from six countries to take them.