The United Nations has called on states not to "backtrack" on pledges made to host migrants and refugees, including from Syria, in the wake of the attacks in Paris.
"We are concerned about the reactions from some states to end programs being put in place, backtracking from commitments made to manage the refugee crisis," said UN refugee agency spokeswoman Melissa Fleming on Tuesday (local time).
"Refugees should not be turned into scapegoats and must not become the secondary victims of these most tragic events," Fleming added, after some EU states indicated they would take a hard line on the migrant crisis following the attacks.
She described as "disturbing" rhetoric from some countries suggesting they might walk back on previously made commitments.
"What's being threatened is an EU plan to manage the arrival of so many people.... We need all the countries in Europe to be on board," Fleming said.
European populist and far-right leaders have seized on the jihadist attacks in Paris to demand the continent stem the record migrant influx.
Hungary's parliament on Tuesday (local time) gave Prime Minister Victor Orban the green light to challenge in court a quota system on taking in migrants, which was previously agreed by EU governments.
France's anti-immigration National Front leader Marine Le Pen called for an "immediate halt" to new arrivals, while Germany's xenophobic PEGIDA movement drew thousands to their latest anti-Islam rally.
Poland's new right-wing, eurosceptic government, which was sworn in on Monday, signalled it would take a harder line on migrants, while honouring previously agreed EU commitments.
Some politicians voicing anti-migrant rhetoric have pointed to the discovery of a Syrian passport near the body of one of the Paris suicide attackers, with French prosecutors saying his fingerprints matched those recorded in October in Greece, the start of the European migrant trail for many.
In the US, nearly half of the 50 US states have moved to shut the door on Syrian refugees as Republican politicians urged a halt to the resettlement program, citing security fears following the Paris attacks.
President Barack Obama pushed back, criticising "shameful" calls to screen the refugees fleeing the war-torn country based on their religion.
But Obama faced a barrage of pressure from at least 22 Republican-led states, GOP presidential candidates, key members of congress, and in one case a Democratic governor to suspend a program to resettle 10,000 Syrian refugees on US soil in 2016.