Sweden has begun ID controls as part of the government's efforts to limit the number of refugees entering the country.
Everyone entering Sweden from midnight on Sunday by bus, train or ferry from Denmark will be checked and those lacking valid ID documents will be turned back.
Sweden, which until recently was known as one of the most welcoming countries in the world for people fleeing wars, has said it can no longer cope as the influx of refugees and migrants reaches record numbers.
With more than 160,000 asylum-seekers arriving to the country of 9.5 million in 2015, mainly from Syria, Iraq and Afghanistan, accommodation for new arrivals is running out.
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"We must get the number of asylum seekers down. ID controls are one way to achieve this," Morgan Johansson, justice and migration minister, said in December.
Of those seeking asylum in Sweden in 2015, about 80 percent lacked passports or equivalent IDs at the time of filing their applications, according to the Swedish Migration Agency.
The controls follow the reintroduction of border checks in Germany, Austria, France, Belgium and several other European countries.
The UN refugee agency, UNHCR, has said refugees will face increasingly slim chances of asylum in Europe should more countries follow Sweden and impose stricter entry requirements.
Mattias Axelsson, UNHCR spokesman in northern Europe, said governments must understand that refugees are under tremendous strain and that those fleeing do not always have the possibility to bring ID documents.
"You can't expect that those who have the right to asylum also have the right documents with them from the beginning, that is simply impossible," he told Swedish news agency TT.
"We follow this with growing concern."
Besides refugees, ID controls will have a big effect on passengers travelling from Denmark, as about 70,000 people - many of them commuters - cross the Oresund bridge each day.
The plans have been heavily criticised by operators and commuters on both sides of the strait, as the controls are expected to add at least half an hour to a journey that normally takes 35 minutes.
Rights groups have also been critical, saying that the ID controls are part of measures that limit refugees' possibilities to seek asylum.
Sweden has seen a decrease in the number of people seeking asylum in recent weeks, following news of tighter border checks and stricter rules for residency permits.
In November, the Migration Agency said Sweden was no longer able to provide shelter for all asylum seekers, saying families with children would be given priority.
Source: Al Jazeera