The Hungarian parliament has approved a law enabling all asylum seekers in the country to be detained and forced back into neighbouring Serbia.

Viktor Orban, the Prime Minister, claimed migrants were keeping his country “under siege”. Speaking at a swearing-in ceremony for a group of specialist guards known as “border hunters”, he said that Hungary could only count on itself for protection.

Mr Orban, leader of the right-wing populist Fidesz party and a supporter of Donald Trump, has already ordered the reinforcement of fences along Hungary’s southern border and claimed refugees are a threat to Europe’s Christian identity and culture.

Hungary jails 10 migrants

The new legislation will see refugees locked in border camps made of shipping containers while their cases are decided.

Applications will be declared inadmissible for anyone who entered Hungary from Serbia or a “safe third country”, while the appeal period will be cut to just three days and migrants may have to cover the costs of their own imprisonment.

The new bill also allows authorities to detain all adult asylum seekers and summarily return those refused to the Serbian border as part of “crisis” measures in place until September.

The UN refugee agency (UNHCR) said it was “deeply concerned” by the measure, which combines with other policies to make it “nearly impossible for asylum-seekers to enter the country, apply for asylum and receive international protection”.

“This new law violates Hungary’s obligations under international and EU laws, and will have a terrible physical and psychological impact on women, children and men who have already greatly suffered,” spokesperson Cécile Pouilly told reporters in Geneva.

“Under international and EU laws, the detention of refugees and asylum seekers can only be justified on a limited number of grounds, and only where it is necessary, reasonable and proportionate … children should never be detained under any conditions.”

Humanitarian organisations had appealed to the European Commission to intervene to block the draft bill, saying it was “at odds with EU, human rights and refugee law” in a letter last month.

The law “on the amendment of certain acts related to increasing the strictness of procedures carried out in the areas of border management”, allows adult asylum seekers including families with children and unaccompanied minors above the age of 14 to be jailed.

How Hungary welcomes its refugees - in pictures Show all 15 1 /15 How Hungary welcomes its refugees - in pictures How Hungary welcomes its refugees - in pictures Serbia-Hungary border Refugees protest as Hungarian riot police fires tear gas and water cannon on the Serbian side of the border, near Roszke How Hungary welcomes its refugees - in pictures Serbia-Hungary border A refugee throws a bottle of water towards Hungarian riot police after they used water cannon to push back refugees at the Hungarian border with Serbia near the town of Horgos How Hungary welcomes its refugees - in pictures Serbia-Hungary border Refugees protest as Hungarian riot police fires tear gas and water cannon at the border crossing with Serbia in Roszke How Hungary welcomes its refugees - in pictures Serbia-Hungary border Hungarian armoured personnel carriers are deployed at the border crossing with Serbia in Roszke How Hungary welcomes its refugees - in pictures Serbia-Hungary border Hungarian riot policemen are deployed at the border crossing with Serbia in Roszke How Hungary welcomes its refugees - in pictures Serbia-Hungary border Hungarian police spray water cannon on migrants at the "Horgos 2" border crossing into Hungary, Serbia How Hungary welcomes its refugees - in pictures Serbia-Hungary border A refugee reacts after Hungarian riot police use water cannon to push back refugees at the Hungarian border with Serbia near the town of Horgos How Hungary welcomes its refugees - in pictures Serbia-Hungary border A refugee gestures as Hungarian riot police use water cannon to push back refugees at the Hungarian border with Serbia near the town of Horgos How Hungary welcomes its refugees - in pictures Serbia-Hungary border A refugee throws a stone towards Hungarian riot police after they used water cannon and pepper spray to push back refugees at the Hungarian border with Serbia near the town of Horgos How Hungary welcomes its refugees - in pictures Serbia-Hungary border Refugees protest as Hungarian riot police fires tear gas and water cannon on the Serbian side of the border, near Roszke How Hungary welcomes its refugees - in pictures Serbia-Hungary border Migrants shout slogans as they stand in front of a barrier at the border with Hungary near the village of Horgos, Serbia How Hungary welcomes its refugees - in pictures Serbia-Hungary border Hungarian riot policemen run as they are deployed at the border crossing with Serbia in Roszke Reuters How Hungary welcomes its refugees - in pictures Serbia-Hungary border Hungarian riot policemen are deployed at the border crossing with Serbia in Roszke Reuters How Hungary welcomes its refugees - in pictures Serbia-Hungary border Refugees stand in front of a barrier at the border with Hungary near the village of Horgos, Serbia Reuters How Hungary welcomes its refugees - in pictures Serbia-Hungary border Refugees wait at the Horgos 2 border crossing EPA

It reinstates Hungary’s previous practice of detaining asylum applicants, which was suspended in 2013 under pressure from the European Union, the UNHCR and the European Court of Human Rights.

The provision to allow authorities to round up migrants and forcibly return them over the Serbian border expands a previous law permitting the push-backs within five miles of the boundary.

The law was approved by 138 votes to six against and 22 abstentions, amid continuing reports of abuse by border police, with migrants claiming to have been beaten, filmed and photographed in “selfies” with officers.

Lydia Gall, a Balkans and Eastern Europe researcher for Human Rights Watch, said it was expected to come into effect with the President’s signature within eight days.

“It makes a mockery of the right to seek asylum,” she told The Independent.

“Of course Hungary has a right to protect its borders and separate asylum seekers from others whose claims do not have merit, but this is not the practice at the border.

“They beat people en masse and push them back over the other side of the fence. That is not allowed under EU law or any other law.”

A migrant injured at the Hungarian border being treated at an MSF facility in Serbia in February (Tahir Mirza/MSF)

An estimated 7,000 asylum seekers are currently stranded in dire humanitarian conditions in Serbia while waiting to cross the border, with only a handful allowed through two designated transit zones a day.

Hundreds of thousands of refugees have crossed into Hungary on their way from the shores of Greece to western Europe but the right-wing government has spared no expense to stop their journeys.

The crackdown is intensifying despite a dramatic fall in the number of refugees journeying to Hungary after the EU-Turkey deal was implemented a year ago to prevent boat crossings to Greece.

Thousands of guards have been deployed to patrol the country’s 100-mile southern border with Serbia, where soldiers and prison inmates are expanding a barbed wire fence into an electrified 13ft barrier.

A spokesperson for the European Commission told The Independent: “We will be analysing the bill when we have been notified by Hungarian authorities but we do not have any further comment to make at this time.”

The Hungarian government has dismissed allegations of mistreatment and abuse, saying authorities were “carrying out their duties lawfully, professionally and proportionately”.

“They place special emphasis on treating migrants humanely and with respect for their human dignity,” a spokesperson added.

“Hungary was one of the first member states to enforce EU rules, and has been protecting the EU’s Schengen borders, stopping, registering and separating out genuine refugees from economic migrants.