- Video report by ITV News Correspondent Geraint Vincent
Three people have died and several others been left injured, a number seriously, in a shooting close to Strasbourg's Christmas market.
French authorities said the gunman was still on the run following the incident around 8pm on Tuesday evening.
The 29-year-old attacker, who has been identified and possesses a criminal record, was reported to have been injured during an exchange of gunfire with a soldier.
French police said that authorities had attempted to arrest the gunman prior to the attack.
A terror investigation has been opened, officials confirmed.
France's interior ministry called on the public to remain indoors, citing a "serious security event".
The European Parliament building is around two miles from the centre of Strasbourg and is on lockdown due to the shooting.
One witness described trying to help a Thai tourist lying on the ground with an apparent head wound after hearing "two distinct noises" which he initially took to be firecrackers.
Peter Fritz told the BBC: "We tried our best to resuscitate him, we applied CPR, we dragged him into a restaurant close by and had help with some medical people from Germany, but it took more than 45 minutes for an ambulance to appear.
"After 45 minutes we were told over the phone by an emergency doctor that any further efforts would be futile.
"He's still here in this restaurant but we have abandoned all hope for him."
- MEP finds himself taking refuge in Strasbourg restaurant
Thorbjorn Jagland, the Secretary General of the Strasbourg-based Council of Europe, said on Twitter: "The police informed me tonight of a shooting in Strasbourg with possibly one victim and several wounded. The perpetrator is still on the run. This is a serious incident and I advise all staff and visitors to stay at home or indoors for the moment."
Sinn Fein MEP Martina Anderson said: "We were in the centre of #Strasbourg town when gun shots went off.
"No confirmed reports but footage out of people on the ground injuries if not worse. My thoughts & prayers with all who are injured."
Labour MEP for Yorkshire and the Humber, Linda McAvan, tweeted: "There's a shooting incident tonight in Strasbourg centre where Xmas market takes place. European Parliament on lock down. I and my staff are safe in the building."
Theresa May described herself as "shocked and saddened" by the attack.
She tweeted: "My thoughts are with all of those affected and with the French people."
Strasbourg Christmas market is one of the oldest in Europe with 300 wooden chalets set up in the city's historic centre from November 23 to Christmas Eve.