The United Nations has said "much more is required" to prevent the deaths of migrants fleeing to Europe after hundreds were reported dead in recent days.
Migrants walk down a railroad towards Hungary near the northern Serbian town of Horgos. Photo: AFP
Secretary-General Ban Ki-moon called for a "collective political response" to avert "a crisis of solidarity".
He called on states involved to "expand safe and legal channels of migration".
On Thursday 71 people, thought to be Syrians, were found dead in a lorry in Austria. Some 200 others are feared dead after two boats sank off Libya.
Mr Ban said he was "horrified and heartbroken" at the latest loss of life.
"A large majority of people undertaking these arduous and dangerous journeys are refugees fleeing from places such as Syria, Iraq and Afghanistan," he said.
"The international community must also show greater determination in resolving conflicts and other problems that leave people little choice but to flee," he added.
Mr Ban called on nations to observe international law on asylum requests, and not to "force people to return to places from which they have fled if there is a well-founded fear of persecution... This is not only a matter of international law; it is also our duty as human beings."
He said: "This is a human tragedy that requires a determined collective political response. It is a crisis of solidarity, not a crisis of numbers."
Mr Ban also urged more action against people smugglers, a call echoed by White House spokesman Josh Earnest.
"The violence and instability in North Africa and the Middle East isn't just destabilising the immediate region but is starting to have a destabilising impact on other regions of the world too, including in Europe," Mr Earnest said.
NZ needs to take more refugees, says council
The Refugee Council says the huge numbers of migrants dying while fleeing their countries, reinforces the need for New Zealand to take in more refugees.
Its president Arif Saeid said New Zealand could help by taking in more people who would otherwise head to Europe.
He is urging the Government to boost the refugee quota by 250, to 1000 people a year.
"This is the time for us, for New Zealand, to increase our quota, to 1000 at least per year, many other countries have increased their quotas."
Mr Saeid said many migrants had escaped war in their home country and would do anything to find a safe place.
Hundreds dead or feared dead
Some 200 people are feared to have drowned after two boats capsized on Thursday as they tried to cross from Zuwara, west of Tripoli in Libya, to Italy.
About 100 bodies have already been found and Libyan workers are continuing to search for 100 other people who are still unaccounted for.
Some survivors were rescued having spent the night in the water, clinging to life jackets.
Migrants rescued by Libyan coastguard after their boat sank. Photo: AFP
While most of the victims of Thursday's capsizes are thought to be from Syria and African countries, a Bangladeshi diplomat told the BBC that at least five Bangladeshi nationals, including a six-month-old baby, were among the dead.
Police in Italy detained 10 suspected traffickers after a separate incident in which 52 people were found dead in the hold of a ship off the coast of Libya on Wednesday.
Meanwhile, Hungarian police said they had arrested four people over the discovery of the bodies of 71 migrants, thought to be Syrians, in an abandoned lorry in Austria, near the Hungarian border.
The victims were 59 men, eight women and four children who are thought to have been dead for about two days.
Officials said the victims probably died after suffocating in the vehicle, before it crossed into Austria from Hungary. Among the victims was a girl aged between one and two years old.
The refrigerated truck, in which bodies of 71 migrants were found, parked at the border in Nickelsdorf, Austria. Photo: AFP
Tens of thousands of migrants from conflict-hit states in the Middle East and Africa have been trying to make their way to Europe in recent months.
A record number of 107,500 migrants crossed the EU's borders last month.
Some of them pay large sums of money to people smugglers to get them through borders illegally.
The UNHCR says more than 2,500 people have died trying to reach Europe so far in 2015, not including Thursday's deaths.
- BBC / RNZ