Fingerprint evidence shows that the gunman overpowered by passengers on a train in France is a Morrocan known to European authorities as a suspected Islamist militant, according to a source familiar with the case.

Two people were wounded in the struggle to subdue the Kalashnikov-toting attacker aboard the high-speed train from Amsterdam to Paris on Friday. Three young Americans, one of whom suffered knife wounds, were among the passengers who stopped the gunman.

French Interior Minister Bernard Cazeneuve told reporters the gunman appeared to be a 26-year-old Moroccan who had been "identified by the Spanish authorities to French intelligence services in February 2014 because of his connections to the radical Islamist movement".

Cazeneuve did not give a name, but the source named him as Ayoub el Khazzani and said he was believed to have flown from Berlin to Istanbul on May 10 this year. Turkey is a preferred flight destination for would-be jihadists heading for Syria.

According to a Spanish counter-terrorism source, Spanish authorities had a suspect they identified as Khazzani under surveillance before he left Spain for France in 2014, traveled to Syria, and then came back to France.

In Spain, he lived in Madrid between 2007 and 2010 before moving to the southern port of Algeciras. He was arrested in Spain at least once for a drug-related offence, the Spanish counter-terrorism source said.

Cazeneuve said he had also lived in Belgium and that inquiries "should establish precisely the activities and travels of this terrorist".

French newspaper Le Voix du Nord said the suspect may have had connections to a group involved in a suspected Islamist shooting in Belgium in January. The Belgian government confirmed an inquiry was under way but would not comment further.

French authorities have been on high alert since January, when 17 people were killed in shootings by Islamist militants in and around Paris.