Doctors Without Borders, also known by its French initials, MSF, said on Tuesday that border closures and tougher policing force people seeking sanctuary or jobs to find more dangerous routes to and through Europe.
"Policies of deterrence, along with their chaotic response to the humanitarian needs of those who flee, actively worsened the conditions of thousands of vulnerable men, women and children," said MSF's head of operations, Brice de le Vingne.
The group urged the EU to create more legal ways to go to Europe, allow asylum applications at the land border between Turkey and Greece and set up a real search and rescue system, after more than 3,000 people died trying to reach the European Union by sea in 2015.
As pressure built among EU partner nations, four Central European members confirmed Tuesday their fierce opposition to a plan to redistribute 160,000 refugees from Italy and Greece and called for the strict control and registration of all refugees on the external borders of the Schengen zone, comprising 26 European nations that allow passport-free travel among them.
The Czech Republic, Hungary, Poland and Slovakia, which make up the informal Visegrad Four group, rejected any compulsory refugee quotas.
Officials from Slovenia and Serbia warned of retaliatory measures if Austria tries to slow the entry of migrants. That, they said, would cause a domino effect and ratchet up tensions along the Balkan migrant corridor back to Greece, where most migrants are arriving from Turkey.
"If Austria and Germany introduce certain measures that would mean tighter control of the flow of migrants, Slovenia will do the same," Slovenia's Foreign Minister Karl Erjavec said.
Serbian Foreign Minister Ivica Dacic said that Belgrade "will protect its interests … We cannot allow the borders to close and limit the flow of migrants so they stay in Serbia."
German Foreign Minister Frank-Walter Steinmeier said closing borders won't prevent people from trying to enter and pass through Europe.
After the MSF report, the EU's top official, European Council President Donald Tusk, said the bloc has just two months to get its migration strategy in order, amid criticism that its current policies are putting thousands of people in danger and creating more business for smugglers.
"We have no more than two months to get things under control," he told EU lawmakers, saying that a summit of EU leaders in Brussels on March 17 and 18 "will be the last moment to see if our strategy works."
Tusk warned that if Europe fails to make the strategy work, "we will face grave consequences, such as the collapse of Schengen."
The EU spent most of 2015 devising policies to cope with the arrival of more than 1 million people fleeing conflict or poverty, but few are having a real impact. A refugee-sharing plan launched in September has barely got off the ground, and countries are still not sending back people who don't qualify for asylum.
A package of sweeteners for Turkey — including $3.3 billion, easier visa access for Turkish citizens and fast tracking of the country's EU membership process — has borne little fruit.