Stockholm (AFP) - Swedish police said Tuesday they had arrested 14 Polish far-right activists for allegedly planning to attack an asylum centre, after finding axes, knives and iron pipes in their cars.

Authorities said they detained the men on Monday after being tipped off about a planned attack against a migrant centre in Nynashamn, some 60 kilometres (37 miles) south of Stockholm.

"They are Polish citizens and they belong to the far-right sphere," police spokesman Lars Alvarsjo told state broadcaster Swedish Radio.

"We believe that the migrant centre was the target of the attack," another police spokesman, Hesam Akbari, told AFP.

Aftonbladet daily reported that some of the suspects were living and working in Sweden.

Last month, dozens of masked men believed to belong to hooligan or neo-Nazi gangs gathered in central Stockholm and distributed leaflets calling for attacks on young migrants.

Three of the 14 men arrested on Monday evening were involved in last month's incident, said Alvarsjo.

Sweden, a country of 9.8 million, took in about 163,000 asylum seekers in 2015, putting it 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 -- triggering the continent's worst migration crisis since World War II.

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

In Sweden, the tougher rules come against the backdrop of rising concern over conditions in the country's overcrowded asylum facilities.

Swedish officials have called for stepped-up security after an employee at a centre for unaccompanied child refugees was fatally stabbed in January.

Sweden expects to receive up to 140,000 additional asylum seekers this year.