Despite his burns, the suspect at Charles de Gaulle was afterwards able to communicate with officers from the General Directorate of Internal Security (DGSI) – France’s domestic security service.

Anti-terrorism prosecutors were also informed, and a formal investigation was opened into a variety of alleged offences.

“Initial findings revealed products and materials intended for the manufacture of explosive devices on site,” a source at France’s national anti-terrorist prosecutor’s office told news outlet BFMTV.

“One of the improvised explosive devices exploded. The hotel had to be evacuated.

“The man, of Russian and Ukrainian nationality, who was conscious despite his injuries, explained to investigators that he had built homemade batteries for mobile phones when one of them exploded.”

Multiple passports found in luggage

Multiple security sources later confirmed that traces of TATP were found at the B&B Hotel rented by the man, who was born in the war-torn Donbas region of Ukraine and who is a Russian speaker, in his own name.

The batteries were covered in plastic, with a match, powder and barbecue lighters inside a package, said the same sources.

On Wednesday, calls to the hotel, which is a short walk away from all the Charles de Gaulle terminals, went unanswered.

As well as bomb-making equipment, DGSI investigators found “multiple passports” in the man’s luggage.

The 2-star B&B tourist hotel – one that is frequently used by British travellers – was immediately evacuated, and on Wednesday remained closed.

It has 226 air conditioned, non-smoking rooms and describes itself as a “cheap and well-located 24-hour check-in hotel”.

Its publicity states that it is “very close to the largest French and Parisian airport, so no more risk of missing your flight”.

The suspect is said to have arrived in France “very recently,” according to another investigating source, and had booked into the B&B Hotel under his own name.

He is now said to be recovering well from his wounds, and cooperating with officials.

Fears Russian agents plotting atrocities 

Anti-terrorism prosecutors confirmed they have opened an investigation into “participation in a terrorist criminal association with a view to preparing crimes of attacks against persons, possession of an incendiary or explosive substance or product or of elements intended to compose an explosive device with a view to preparing destruction, and damage or harm to people, in connection with a terrorist enterprise”.

The man’s arrest follows Donald Tusk, the Polish prime minister, warning of Moscow-run agents plotting atrocities in Europe.

In May, Mr Tusk said nine people have been arrested for allegedly preparing acts of sabotage in EU member states in co-ordination with Russian intelligence.

He said those detained were Belarusian, Polish and Ukrainian citizens, possibly recruited from organised crime groups.

All were accused of “beatings, arson and attempted arson”, and were “directly implicated in the name of Russian services in acts of sabotage in Poland”.

They were also suspected of preparing attacks in Lithuania, Latvia and possibly Sweden, he said.

Multiple European intelligence agencies have also warned their governments that Russia was planning violent acts across the continent.