In a letter to the Commissioner for Human Rights of the Council of Europe, the government said there was no data on unlawful detention, injury or ill treatment of refugees, migrants or asylum seekers.

An investigation by Sky News, Lighthouse Reports and European media partners uncovered allegations of abuses against asylum seekers taking place in a makeshift jail run by Bulgarian border forces.

"When they caught us, they beat the hell out of us... they stripped us naked... shaved our brows with a Gillette razor," said Nackman, a 34-year-old refugee who claims he was detained for several hours in the so-called "cage" in Sredets.

"Then there was this wooden room that could only fit 20 people, but they forced 60 people into it; even an animal couldn't survive in that wooden room. It has the worst odour ever, so if you need to use the toilet, you'll just go to the side. They won't look at you with human eyes."

Other asylum seekers claimed they were held for several days. Some reported they were attacked by dogs, beaten and humiliated by officials before being forced back to Turkey.

"After they threw me in the container, they unleashed the dogs. It was me and a young child. He was 12 years old. He was bitten by the dogs and so was I," one man said.

Bulgaria has also been accused of shooting a refugee after a video emerged showing a young Syrian man being fired at on the border with Turkey.

Abdullah El Rustum, 19, said a bullet fired by border officials went through his hand and into his chest on 3 October.

He claimed it happened after he was caught with a group of asylum seekers and pushed back over the border to Turkey.

Bulgaria has denied allegations of violence and said "no shots were fired from our side".

The government also said it followed international and domestic law and released photos of damage it said was caused by stones thrown by the group.

It alleged an officer was also injured.

Read more:
Refugee shot near Bulgaria-Turkey border
Asylum seekers 'abused in cage' by Bulgarian forces

Following the media coverage, the Council of Europe's human rights commissioner wrote to the prime minister and the deputy prime minister for public order and security expressing her concern.

She also requested information on the investigations launched by the Bulgarian authorities into allegations of unlawful detention and ill-treatment.

"Bulgaria strictly observes international humanitarian and human rights law," the government wrote in reply on Tuesday, adding border guards' actions were under constant surveillance. "All measures to ensure effective border management and control are applied while guaranteeing the fundamental rights and freedoms of all persons, including the right of asylum."

Bulgaria is often used as a gateway by people trying to get to other places in Europe.

More than 153,000 people tried to cross the Bulgarian-Turkish border between January and 27 November 2022.

That's four times as many as the same time last year, according to the Ministry of Information.

Authorities say they have seen a rise in violence from migrants and traffickers and are investigating the deaths of three police officers killed during anti-smuggling operations.