The Home Secretary, who was attending talks with European Union counterparts aimed at responding to the emergency, stressed that the UK was playing a role in the search and rescue mission and the effort to target the gangs “making a profit out of human lives”.
European home affairs ministers met in Luxembourg to try to hammer out a joint strategy for dealing with the flow of people crossing the Mediterranean.
The European Commission has proposed redistributing around 60,000 Syrian and Eritrean asylum seekers from Italy and Greece to other member states.
But the quota plan is being resisted by a number of countries in the borderless Schengen zone, while Britain has indicated it will use an opt-out to avoid taking part.
Save The Children stepped up the pressure on UK ministers by calling for Britain to agree to take in 1,500 unaccompanied youngsters who had made the crossing to Europe.
Arriving in Luxembourg Mrs May said: “The crisis in terms of migrants who cross the Mediterranean is a problem in two ways. First of all, obviously, lives are being put at risk but secondly, as we see in Calais and elsewhere, it’s putting great pressure on European towns and cities which is even reaching to our borders, although we are not part of the borderless Schengen area.
“To deal with this issue in the long term we need to go after the criminal gangs who are plying a terrible, callous trade in human lives.
“We also need to break the link between people getting into the boats and reaching Europe. That means returning people to North Africa or elsewhere, or to their home countries, so that they see that there is no merit in this journey. It also means development work in the countries of origin so that we can ensure people no longer have the same incentive to try to get into these boats and risk their lives.”
Asked about the British response, Mrs May said: “The UK is working with other European countries in a number of ways. We are putting effort into the search and rescue that is taking place – HMS Bulwark but also two Border Force cutters.
“Of course as the UK we also put effort into development aid to help these countries, to stabilise them, to provide the economy that means there is no longer the incentive for the journey.”
Italian prime minister Matteo Renzi upped the ante by suggesting he could begin granting temporary residence permits, which would allow the arrivals free movement into Schengen states.
Mr Renzi insisted it was unacceptable that his country was having to bear the brunt of the migration. “If the European Council chooses solidarity, then good. If it doesn’t we have a Plan B ready but that would be a wound inflicted on Europe,” he said.