Sweden expects to expel up to 80,000 asylum-seekers whose applications have been rejected, its interior minister was quoted as saying.
Anders Ygeman said that charter aircraft would be used to deport the migrants over several years.
“We are talking about 60,000 people but the number could climb to 80,000,” Swedish media quoted him as saying.
Some 163,000 migrants applied for asylum in Sweden in 2015, the highest per capita number in Europe.
Of the approximately 58,800 cases processed last year, 55% were accepted.
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Earlier on Wednesday, Greece’s government responded to allegations in a draft European Commission report that it had “seriously neglected” its obligations to control the external frontier of Europe’s passport-free Schengen zone.
Greek government spokeswoman Olga Gerovasili accused the Commission of “blame games” and said it had failed to act on a programme agreed last year to relocate tens of thousands of migrants and refugees stranded in Greece.
Europe is struggling to deal with a crisis that has seen tens of thousands more migrants arrive on Greek beaches, undeterred by cold wintry conditions.
The UN says more than 46,000 people have arrived in Greece so far this year, with more than 170 people killed making the dangerous crossing.
Mr Ygeman was quoted as giving the figure of 80,000 by Swedish Public TV and Dagens Industri business newspaper (in Swedish).
He later tweeted to say he had not taken a position on how many migrants had grounds for asylum, it being a matter for the authorities and the courts.
Sweden recently introduced temporary border checks in a bid to control the influx of people. Along with Germany, the Scandinavian country is is a prime destination for refugees and other migrants entering the EU illegally.