The UK will play a "huge and historic role" in helping to tackle the migration crisis, David Cameron said as he promised to step up efforts to "smash" the criminal gangs behind the problem.
The Prime Minister said it was "the biggest problem facing Europe today", with a movement of people greater than any seen since the end of the Second World War.
Mr Cameron said the UK's aid programme meant it could help address some of the factors that led people to flee their homelands for a new life in Europe while its military power meant it could tackle the human traffickers.
The Prime Minister was speaking as a major international summit bringing together European and African nations began in Malta.
He called for a new "resolve" to tackle the problem as he addressed the company of Royal Navy warship HMS Bulwark in Valletta harbour.
Mr Cameron said the UK was a "moral nation" which was involved in efforts to tackle the humanitarian crisis.
He added: "Saving lives is not going to be enough. We need a real partnership with the countries from which these people are coming and that is what this summit in Malta is all about, bringing together the countries of Africa, the countries of Europe, so we can work together.
"Britain will play a huge and historic role. Our aid programme means we can get into those countries and tackle not just the poverty but the failures of government, the corruption, the conflict and all the things that cause people to leave their homes and make this perilous journey.
"As well as responding with humanity and with partnership, we also have to respond with resolve and that is what the next stage of this mission is going to be about.
"Because, to be frank, it's not enough just to pick people up and save their lives, we have got to go after the criminal gangs that were loading them into the boats and offering them the false hope in the first place."
He told HMS Bulwark's crew: "We need to smash those gangs and that is what the next stage of this work is going to be about.
"It will be difficult work but it's absolutely essential and we will give you everything you need to make sure that work gets done properly.
"In the end we have to break the link between getting on the boat and getting the chance to come to Europe.
"As long as that ability to do that is there, the criminal gangs keep on exploiting people in the way they are today.
"So, we know what needs to be done - the humanity of a moral nation, the partnership of a country that acts with others to get things done in the world and a country that knows resolve is going to be absolutely key to dealing with this."
He said the UK was the only "major country" meeting both its Nato commitment to spend 2% on defence and 0.7% of gross national income on aid.
"We are the engaged nation that recognises the hard military power that this great ship represents but also the incredibly important soft power of an aid programme that can help knit together and mend the countries from which so many people are coming," he said.
Amphibious assault ship HMS Bulwark was despatched to the Mediterranean in April to help rescue migrants attempting the treacherous crossing from North Africa to Europe.
Mr Cameron told the crew: "You should be incredibly proud of the lives you have saved. There will be people who will live out extraordinary dreams and lives that wouldn't have happened were it not for what you have done in the Mediterranean."