The EU has authorised the arrest people traffickers in international waters, with operatings taking effect from 7 October.
European warships will be used against traffickers if they are within international waters and do not go into Libyan territory, foreign affairs chief Federica Mogherini said.
The EU had already recently approved the use of military force against migrant traffickers, including the seizure of boats used to carry people across the Mediterranean.
The first phase concentrated on reconnaissance, surveillance and intelligence gathering, and involved speaking to migrants rescued at sea and compiling data on trafficker networks.
"We have now a complete picture of how, when and where the smugglers' organisations and networks are operating so that we are ready to actively dismantle them," Mogherini said. From October, "we will be able to board, search, seize vessels in international waters, (and) suspected smugglers and traffickers apprehended will be transferred to the Italian judicial authorities".
She added they were striving to create a legal framework to extend the operation into Libyan territorial waters.
