It comes as a Belgian mayor suggested a ban on male refugees at pools

Swedish police are to send undercover officers in a bid to prevent attacks

Swedish police have resorted to sending undercover officers to Stockholm's swimming pools amid a rising number of sex assaults on girls by migrants.

Plain clothes police will monitor swimming baths in the Swedish capital after 'a few dozen' suspected cases of sexual harassment were reported mainly by parents of teenage girls.

It comes amid reports that a number of girls said they had been sexually assaulted by young male asylum seekers at the city's Eriksdalsbadet Olympic baths in the past three weeks.

The four cases involve girls under the age of 18 and have taken place in hot tubs, pools or in the changing rooms of Eriksdalsbadet, Stockholm (pictured), in the past three weeks

Swedish police have resorted to sending undercover officers to a Stockholm's swimming pools amid a rising number of sex assaults on girls by migrants (file picture)

The four cases involve girls under the age of 18 and all sexual assaults have taken place in hot tubs, pools or in the changing rooms.

The baths have started segregated whirlpool bathing after an increase in reports by girls and women that they had been groped underwater.

Stockholm Police spokesman Kjell Lindgren did not want to comment on the suspected perpetrators except to say they were mostly boys or young men.

But police have said there has been an increase in reports of sexual assaults against women by foreign men.

Lindgren said measures were also being adopted at the Eriksdals baths.

'We do not wish to point fingers to a specific group, but we are talking about boys without a parent or guardian,' Stockholm City police chief Elisabeth Anestad told Expressen.

Eriksdalsbadet, which is the biggest aquatics centre in Stockholm, has previously reported a spike in sexual assaults - mainly incidents involving boys and young men groping women.

As a result, Stockholm police will not have uniformed police regularly patrolling the swimming centre, and the pool's hot tubs are now segregated by sex.

Marc Vanden Bussche, mayor of Kokzijde, Belgium, has proposed a temporary ban on male asylum seekers in the town's public pools

It comes as a Belgian mayor announced that he would propose banning male refugees from a swimming pool for a month on Monday after complaints from female bathers.

'We had women complain because they felt stared at and selfies had been taken with them. It's escalating. We never had any complaints before,' said Marc Vanden Bussche, mayor of the coastal town of Kokzijde.

Bussche said he had decided to act after police were called in to investigate an Iraqi man who had caught an 11-year-old girl as she came off a slide.

The politician from the Dutch-speaking liberal party Open VLD, said he would propose a one-month ban at a council meeting on Monday to allow tempers to cool. The town recently took in 300 asylum seekers.

'In the meantime we will teach them about our way of life and explain the rules of the pool to them,' he said, adding the ban would not affect children and their mothers.

Belgium's state secretary for migration, Theo Francken, advised against the move.

'It's never wise to punish a whole group for the transgressions of a few,' he said in a tweet. 'Asylum seekers live in open centres, they're free to go swimming. But hands off!'

These are only the latest incidents reported in mainland Europe in recent weeks involving sexual assaults allegedly committed by male asylum seekers in public swimming pools.

The German town of Bornheim, 19 miles south of Cologne, temporarily banned male asylum seekers from its pool this month after receiving complaints of sexual harassment.

Last week, the historic baths Johannisbad baths in Zwickau, Saxony banned all migrants after male asylum seekers had been caught masturbating in a hot tub and sexually assaulting women.