A top European Union official has warned that migrant ghettos could become a 'nuclear bomb' of unrest and has urged the European Union to tackle the problem.

The EU has a war chest of £310 billion to spend by 2020 on its so-called cohesion policy as it tries to reduce inequality across the union.

European Commissioner for regional policy Corina Cretu says that the money is crucial to stop the segregation of migrants in harsh and dangerous ghettos.

European Commissioner for regional policy Corina Cretu has warned the EU that migrant ghettos could become a 'nuclear bomb' of civil arrest

Despite decades of spending on infrastructure in the poorer parts of Europe, the European Union is aiming to reduce inequality by pumping more money into countries in eastern and southern Europe.

Ms Cretu said that this is important for 'social integration'.

She told the Thomson Reuters Foundation this week at the World Urban Forum in Kuala Lumpur, Malaysia: 'Social integration will be crucial in the years to come.

'If we allow ghettos or segregation of migrants, this will become a nuclear bomb in the future.'

Corina Cretu (pictured) said: 'If we allow ghettos or segregation of migrants, this will become a nuclear bomb in the future'

The EU asylum system was on the brink of collapse in 2015 as a million refugees and migrants arrived by boat, overwhelming Greece and Italy.

Poland, Hungary, Slovakia and the Czech Republic refused to take some of the new arrivals.

The dispute ended up in the courts and has weakened the bloc's unity, spilling over to other policy areas.

European Union interior ministers are now struggling with the politically charged issue of reforming the union's asylum system.

A group of migrants in Calais (pictured) as Ms Cretu says: 'If we allow ghettos or segregation of migrants, this will become a nuclear bomb in the future'

Former communist states continue to defy pressure from other European capitals to accept refugees travelling across the Mediterranean which would ease the burden on nations such as Greece and wealthy destination countries like Germany.

Ms Cretu, who oversees the cohesion policy, highlighted recent investments on the frontlines of Europe's migrant crisis - from the purchase of two rescue boats for Italian authorities to a support network for mayors of cities wrestling with migration.

When residents and migrants clash, 'mayors are in the middle', Ms Cretu said, citing the tiny Greek island of Chios, where arrivals of refugees and migrants have risen recently.

The European Union is using a new approach to measure inequality, which should give policy makers a better understanding of which areas are most in need, according to Cretu.

Poland, Hungary, Slovakia and the Czech Republic have refused to take migrants in the past, causing tensions with nations like Greece and Italy

She said: 'GDP per capita is not very accurate because it doesn't take into account these pockets of poverty unemployment.'

Ms Cretu also believes that while the cohesion policy's biggest achievements to-date have been in traditional infrastructure, basic needs have been neglected in many parts of eastern Europe.

She said: 'We have still people who are dying because of the quality of water, because the networks were built 40-50 years ago.'