Sweden said it expects to expel up to 80,000 migrants whose asylum requests will likely be rejected, as another 18 people including children drowned off Greece Thursday in a desperate bid to reach Europe.

As the continent grapples with efforts to stem a record flow of migrants, Swedish Interior Minister Anders Ygeman said the mass expulsions of people who arrived in the Scandinavian country last year would require the use of specially chartered aircraft and be staggered over several years.

"We are talking about 60,000 people but the number could climb to 80,000," he told Swedish media, adding that police and migration authorities had been tasked with organising the scheme.

Of the 58,800 asylum requests handled by Swedish migration authorities last year, 55 percent were accepted. Many of those requests were however submitted in 2014, before the large migrant flow began.

Ygeman said he used the 55 percent figure to estimate that around half of the 163,000 asylum requests received in 2015 would likely be rejected.

Sweden, a country of 9.8 million, is among the European Union states with the highest proportion of refugees per capita.

More than one million people travelled to Europe last year -- the majority of them refugees fleeing conflict in Syria, Iraq and Afghanistan -- in the continent's worst migration crisis since World War II.

Most cross by boat from Turkey to Greece and the United Nations says more than 46,000 people have turned up on the EU member's beaches so far this year, while 170 people died making the dangerous journey.

Flimsy boats packed with migrants are still arriving on Greek beaches every day, the passengers undeterred by Europe's cold wintry conditions.

On Thursday, the bodies of 18 migrants, including nine children, were discovered off the Greek island of Samos after their boat capsized and 17 others were still missing, the Greek coastguard said, a day after seven other bodies were found near the island of Kos.

With the influx showing little sign of abating despite the cold weather, many countries -- including Austria, Germany, Denmark, Sweden, France -- have tightened their asylum rules in a bid to discourage new arrivals.

Reflecting the mounting tensions, Brussels on Wednesday blasted Greece's handling of the crisis and warned it could face border controls with the EU's passport-free Schengen zone if it does not protect the bloc's frontiers.

Athens is worried its border with Macedonia will be closed, leaving refugees trapped in the country.

After having closed its border for several hours last week, Macedonia again blocked refugees from entering at its southern border with Greece for three hours overnight.

An interior ministry official said that was because 600 people were queuing at Macedonia's northern border to cross into Serbia.

Several hours later the refugees were allowed on their way and the situation returned to normal. Some 3,000 people were on Thursday waiting at the Macedonian border on the Greek side, police there said.

Greece is not the only country under fire -- Denmark has faced heavy criticism after its lawmakers passed a bill this week allowing authorities to seize valuables from refugees in a bid to deter new arrivals.

Some have likened the move to the Nazis' confiscation of gold from Jews during the Holocaust, with Human Rights Watch denouncing the bill as "despicable".

Neighbouring Sweden has seen the number of new migrants entering the country fall since it brought in systematic photo ID checks on travellers on January 4.

Concerns have been growing over conditions in Sweden's overcrowded asylum facilities, however, and on Tuesday officials called for greater security the day after an employee at a refugee centre for unaccompanied youths was stabbed to death.

A young male allegedly attacked the 22-year-old employee, named by local media as Alexandra Mezher whose parents were from Lebanon, at a centre for youngsters in Molndal, near Gothenburg on Sweden's west coast.

Her death has led to questions about conditions inside some centres, with too few adults and employees to take care of children, many traumatised by war.

Sweden's National Police Commissioner Dan Eliasson earlier this week requested 4,100 additional officers and support staff to help counter terrorism, deport migrants and police asylum facilities.Sweden said it expects to expel up to 80,000 migrants whose asylum requests will likely be rejected, as another 18 people including children drowned off Greece Thursday in a desperate bid to reach Europe.

As the continent grapples with efforts to stem a record flow of migrants, Swedish Interior Minister Anders Ygeman said the mass expulsions of people who arrived in the Scandinavian country last year would require the use of specially chartered aircraft and be staggered over several years.

"We are talking about 60,000 people but the number could climb to 80,000," he told Swedish media, adding that police and migration authorities had been tasked with organising the scheme.

Of the 58,800 asylum requests handled by Swedish migration authorities last year, 55 percent were accepted. Many of those requests were however submitted in 2014, before the large migrant flow began.

Ygeman said he used the 55 percent figure to estimate that around half of the 163,000 asylum requests received in 2015 would likely be rejected.

Sweden, a country of 9.8 million, is among the European Union states with the highest proportion of refugees per capita.

More than one million people travelled to Europe last year -- the majority of them refugees fleeing conflict in Syria, Iraq and Afghanistan -- in the continent's worst migration crisis since World War II.

Most cross by boat from Turkey to Greece and the United Nations says more than 46,000 people have turned up on the EU member's beaches so far this year, while 170 people died making the dangerous journey.

Flimsy boats packed with migrants are still arriving on Greek beaches every day, the passengers undeterred by Europe's cold wintry conditions.

On Thursday, the bodies of 18 migrants, including nine children, were discovered off the Greek island of Samos after their boat capsized and 17 others were still missing, the Greek coastguard said, a day after seven other bodies were found near the island of Kos.

With the influx showing little sign of abating despite the cold weather, many countries -- including Austria, Germany, Denmark, Sweden, France -- have tightened their asylum rules in a bid to discourage new arrivals.

Reflecting the mounting tensions, Brussels on Wednesday blasted Greece's handling of the crisis and warned it could face border controls with the EU's passport-free Schengen zone if it does not protect the bloc's frontiers.

Athens is worried its border with Macedonia will be closed, leaving refugees trapped in the country.

After having closed its border for several hours last week, Macedonia again blocked refugees from entering at its southern border with Greece for three hours overnight.

An interior ministry official said that was because 600 people were queuing at Macedonia's northern border to cross into Serbia.

Several hours later the refugees were allowed on their way and the situation returned to normal. Some 3,000 people were on Thursday waiting at the Macedonian border on the Greek side, police there said.

Greece is not the only country under fire -- Denmark has faced heavy criticism after its lawmakers passed a bill this week allowing authorities to seize valuables from refugees in a bid to deter new arrivals.

Some have likened the move to the Nazis' confiscation of gold from Jews during the Holocaust, with Human Rights Watch denouncing the bill as "despicable".

Neighbouring Sweden has seen the number of new migrants entering the country fall since it brought in systematic photo ID checks on travellers on January 4.

Concerns have been growing over conditions in Sweden's overcrowded asylum facilities, however, and on Tuesday officials called for greater security the day after an employee at a refugee centre for unaccompanied youths was stabbed to death.

A young male allegedly attacked the 22-year-old employee, named by local media as Alexandra Mezher whose parents were from Lebanon, at a centre for youngsters in Molndal, near Gothenburg on Sweden's west coast.

Her death has led to questions about conditions inside some centres, with too few adults and employees to take care of children, many traumatised by war.

Sweden's National Police Commissioner Dan Eliasson earlier this week requested 4,100 additional officers and support staff to help counter terrorism, deport migrants and police asylum facilities.