STOCKHOLM (Reuters) – Sweden is likely to deport up to half last year’s record 163,000 asylum seekers either voluntarily or forcibly, presenting a major challenge to authorities, Interior Minister Anders Ygeman said on Thursday.

Between 60,000 and 80,000 people will likely have to leave, Ygeman said, which would represent about 45 percent of the total number of applicants.

Sweden, with a population of almost 10 million, is one of the countries that has borne the brunt of Europe’s migrant crisis as hundreds of thousands of refugees fleeing war and poverty in the Middle East and north Africa have moved north to wealthier members of the European Union.

Germany took in an unprecedented 1.1 million migrants last year.

Both countries have tightened asylum rules to stem the flow and force other countries to share the burden.

The Swedish government fears many people whose applications for asylum are rejected will go into hiding. Police will seek to find and deport them.

Of the 13,000 sent back from Sweden last year, 10,000 went voluntarily whereas 3,000 were forcibly deported.

Over the past few years Sweden has rejected about 45 percent of claims for asylum, but with last year’s record influx the greater numbers are putting an increasing strain on immigration and police authorities.

“We have a big challenge ahead of us. We will need to use more resources for this and we must have better cooperation between authorities,” Ygeman was quoted as saying by daily Dagens Industri.

Adding to the problem is a backlog of applications. The Migration Agency says recent arrivals will have to wait between 15 and 24 months just to have their applications assessed.

Ygeman said he thought chartered planes would be more widely used and hoped flights could be coordinated with Germany.

Germany deported 20,000 foreigners last year.

Sweden reversed its open door immigration policy late last year and has introduced border controls and identity checks to stem the flow of asylum seekers.

It is also working on making it more difficult for companies to hire immigrants without proper documents to decrease the incentives to stay in Sweden.

This week, Prime Minister Stefan Lofven promised more resources for police to deal with the increased workload because of the refugee situation.

(Reporting by Daniel Dickson and Johan Ahlander; Editing by Robert Birsel and Janet Lawrence)