Migrants waiting at the border between Italy and France in the city of Ventimiglia, Italy, in June 2015.
CNN  — 

Child migrants are being abused, detained and returned to Italy illegally by French police, according to a report published Friday by the charity Oxfam.

Some children trying to cross the border near the Italian coastal town of Ventimiglia have had their mobile phones seized and SIM cards stolen by the authorities, while others have been sent back to Italy after having had the soles of their shoes cut off, according to the report.

“French police officers are not upholding international standards,” said Chiara Romagno from Oxfam Italy. “It’s unacceptable. Besides pushing them back illegally, without offering any guarantees, against the law, they taunt them and mistreat them.”

The French interior ministry did not respond to a request for comment from CNN.

Earlier this year, an administrative tribunal in Nice ruled that the police violated legislation in 20 separate cases of unaccompanied children who were detained and returned across the border to Italy.

But there is no indication yet that the treatment of migrants at the border is improving.

Since June 2015 – when France first clamped down on its Italian border and sent armored vehicles to the frontier near Ventimiglia – men, women and children trying to cross into France to claim asylum, rejoin family members or look for work have had little success.

In 2017, almost 23,000 people traveled through Ventimiglia. The figure in 2018 so far is 4,231, which is likely to increase rapidly as the weather improves, according to Oxfam.

One in four are unaccompanied children and the number of single women, vulnerable to abuse and trafficking, is increasing.

Italian police officers surround a family of migrants during an operation to remove them from the Italian-French border in the Italian city of Ventimiglia on June, 16, 2015.

Rough sleeping, abuse, detention

Unable to enter France, thousands have taken up residence in Ventimiglia but receive little support from the Italian authorities. Many have been ejected from or chosen to leave the Italian asylum system, under which asylum seekers may wait months or years for a decision on their case and live with the threat of prolonged detention in reception hotspots and wrongful deportation.

Some live in the overcrowded and heavily policed Roja Camp outside the town but many, fearful of the police presence, sleep under a flyover instead.

Many of them wash in the nearby river and survive on one meal a day, provided by volunteers, the report says.

The prefecture of Ventimiglia did not respond to a request for comment from CNN.

An informal camp set up by migrants under a flyover in Ventimiglia.

Attempts to cross the border regularly fail. As well as facing physical and verbal abuse from the French police, unaccompanied children are frequently denied their right to claim asylum or detained overnight without food, water, blankets or access to interpreters or lawyers, the report says.

There are also instances of French police changing the birth date on statements, so a child migrant can be treated as an adult and legally pushed back to Italy, according to Oxfam.

Adults are forced to walk the 6.2 miles (10 kilometers) back to Ventimiglia on foot, Oxfam reports. “It is also very dangerous, because in many cases the pavement is missing,” said Simone Alterisio from Italian NGO Diaconia Valdese. “Along that road, we met people walking back under the rain or the burning sun. The last person we met was a very young Eritrean girl holding her 40-day-old baby in her arms.”

In December 2017, a migrant washes his shoes in the river Roya, which runs through the town of Venitmiglia.

Crackdowns on migrants and refugees

It is not the first time that France and Italy have come under fire for their treatment of migrants and refugees. Both nations have been enacting increasingly restrictive, anti-immigrant policies since 2015 and have pledged further crackdowns.

Italy’s new hardline interior minister, Matteo Salvini, made headlines earlier this week when he refused to allow a search-and-rescue ship carrying 630 migrants rescued in the Mediterranean to dock in an Italian port.

The country’s right-wing politicians have long complained that current European Union laws mean that the heaviest responsibility for hosting migrants arriving on European shores falls on the coastal nations, including Italy, Spain and Greece.

During the recent election campaign, Salvini pledged to deport half a million migrants and has since insisted that Italy must not be “Europe’s refugee camp.”

French President Emmanuel Macron criticized Salvini’s actions earlier this week, accusing the Italian government of “cynicism and irresponsibility” for refusing to allow the ship to dock.

Yet Macron has also pledged to crack down on “illegal routes” through Europe and earlier this year described the migrant camp in Calais as “an illegal occupation.”

Under his leadership, the lower house of the French National Assembly passed an immigration law earlier this year that introduces a one-year prison sentence for illegal entry into the country.