The European Union has launched a naval operation against people-smugglers in the Mediterranean as part of the effort to tackle the flow of migrants from Africa.
The first phase of the operation will focus on surveillance and assessment of the criminal networks behind the boats attempting to make the dangerous crossing, but later stages of the plan could involve direct action against the smugglers.
A United Nations Security Council resolution will be needed before the later stages of the mission can begin.
EU foreign affairs chief Federica Mogherini said: "With this operation, we are targeting the business model of those who benefit from the misery of migrants. But it's only a part of a broader strategy including the co-operation with our partners in Africa, particularly in the Sahel region, and the work with the International Organisation for Migration and the UNHCR.
"As EU, we are determined to contribute to save lives, dismantle the networks of the smugglers of human beings and address the root causes of migration."
Foreign Secretary Philip Hammond said: " It will be a phased operation and of course we need United Nations Security Council resolutions to commence later phases of the operation but the early phases will begin immediately."
Speaking at a Luxembourg meeting of European foreign ministers, Mr Hammond said the plan would also involve working with African countries to " stop the pressures that are driving this wave of migration towards Europe".
The second stage of the EU operation will allow for the search and seizure of suspicious vessels, while the third phase would permit the "disposal of vessels and related assets, preferably before use" and to "apprehend traffickers and smugglers".
Britain is deploying survey vessel HMS Enterprise to the region to take over from HMS Bulwark early next month. A British Merlin helicopter will continue taking part in operations.
With GCHQ - Britain's listening post in Cheltenham - said to be tracking the activities of smuggling gangs moving people to the Libyan coast, Defence Secretary Michael Fallon indicated that he wanted to see more intelligence-sharing.
"It is a European problem now, perhaps half a million people trying to cross this year. We know already the traffickers are ringing the Italian coastguard and telling them when the boats are setting off," he told BBC1's Andrew Marr Show yesterday.
Asked whether the EU could consider a naval blockade of the northern coast of Africa, the Cabinet minister replied: "That is a matter for Europe to look to see. It is a very long coast.
"That is a difficult operation. I think what is more important is to pool the intelligence we have to go much further back in Africa."
Downing Street said HMS Enterprise offered greater intelligence-gathering capabilities than HMS Bulwark, which has played a leading part in the search and rescue mission.
The Prime Minister's official spokeswoman said: "One of the benefits that HMS Enterprise will bring is that she is a multi-role survey vessel and will enable us to play a role in terms of the intelligence-gathering, which is the first phase of this CSDP (common security and defence policy) operation.
"Alongside that, GCHQ will be working as part of this and looking at analysing information and building a better picture of the smuggling and trafficking gangs."
Officers from the National Crime Agency are ready to join the EU "intelligence fusion cell" in Sicily, the spokeswoman added.