A heavily-armed gunman overpowered by passengers on a crowded train is “dumbfounded” by allegations of terrorism and denies any shot was fired, his lawyer says.

The alleged attacker, named as 25-year-old Moroccan national Ayoub El Khazzani, on Friday evening boarded a high-speed train in Brussels bound for Paris armed with a Kalashnikov assault rifle, Luger automatic pistol, nine cartridge clips and a box-cutter.

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Witnesses say he opened fire, injuring a man before being wrestled to the floor by three American passengers and tied up, until the train stopped in the northern French city of Arras where he was taken into police custody.

Sophie David, a lawyer assigned to his case at the beginning of his detention in Arras but who is no longer representing him, said he denies firing a single shot.

“He is dumbfounded that his act is being linked to terrorism,” she said, adding the suspect who is believed to have lived in Belgium describes himself as a homeless man.

“He says that by chance he found a suitcase with a weapon, with a telephone, hidden away.

“He said he found it in the park which is just next to the Midi Station in Brussels, where he often sleeps with other homeless people.”

According to Khazzani, who does not speak French and whose comments were translated by an interpreter, he boarded the train to rob people, and had intended to break a window and jump out to escape.

Ms David said that when she told him some people were injured, he was “flabbergasted”.

“He says that the Kalashnikov didn’t work and he was brought under control immediately without a single shot being fired,” Ms David said.

She is no longer his lawyer as Khazzani has since been transferred to Levallois-Perret near Paris where he is being questioned by counter-terrorism officers.

Under French law, suspects in probes related to alleged terrorism can be questioned for up to 96 hours, which means Khazzani could remain in custody until Tuesday evening.

Armed with the weapons, the attacker exited a toilet cubicle on the high-speed train just after it crossed from Belgium into northern France.

A French passenger who happened to be there tried to disarm Khazzani — described as “small, slim, not very strong” — but he got away and fired at least one shot, wounding a Franco-American traveller in his 50s.

But the attack was quickly stopped when two off-duty US servicemen and their friend charged the gunman and restrained him.