Germany was the victim of a suspected mass terror attack last night after a lorry ploughed into a busy Christmas market in Berlin.
At least nine people were killed and more than 50 injured after the vehicle mounted the pavement at about 60kph.
The driver was reported to have fled but was later said to be being held by police. A passenger in the lorry - which came from Poland and may have been hijacked - was later found dead inside.
Police said the incident - which echoed an attack in Nice in July this year where 86 people were killed by a truck driven by an Isil-inspired terrorist - appeared to be deliberate.
Last night they arrested one suspect close to the scene of the attack and warned local residents to stay indoors.
German Chancellor Angela Merkel expressed her sympathy for the victims of the incident.
Taoiseach Enda Kenny also spoke out against the 'barbaric' attack and condemed the acts of violence in Zurich and Turkey. "These acts of violence have no place in society and constitute an attack on our fundamental values," Mr Kenny said.
Germany has been on high alert for a major terror attack ever since Mrs Merkel opened the country's borders to more than one million refugees from the Middle East.
Within minutes of last night's incident, far-right politicians were criticised for exploiting the attack to suggest that Germany's generosity had allowed extremists into the country.
The carnage came just hours after the Russian ambassador to Turkey had been shot dead in the Turkish capital Ankara by a policeman who claimed to be taking revenge for Moscow's involvement in the battle for Aleppo.
And it followed warnings that Isil terrorists may target Christmas markets in Europe.
Witnesses of the Berlin attack described scenes of panic and horror as a lorry veered off the street and ploughed into the crowded Christmas market just off the famous shopping street of Kurfurstendamm at around 8pm local time.
"We were enjoying the Christmas lights and mulled wine. We were ready to get up when we heard a loud bang, To our left we saw Christmas lights torn down and the top of an articulated lorry crashing through the stalls and through people," Emma Rushton, a tourist, told CNN.
"We wanted to get out as soon as possible. We wanted to get to a safe place.
"From my opinion, it was going at 60kmh, there was no sign it was slowing down. It did not feel like an accident.
"There was no way it could have come off like an accident, it was through the middle of the market. The stall where mulled wine was being served was crushed. I saw people bleeding, lying in the pavement."
Crushed stalls were left in the remains of the Christmas market last night, in the shadow of the Kaiser Wilhelm Memorial Church, which is preserved in ruins from World War II bombing.
Other witnesses described bystanders rushing to the aid of the injured. Many of the injured were said to be in a life-threatening condition last night.
The driver of the lorry was believed to be being held by police. Witnesses described him as Eastern European in appearance.
The truck belonged to a Polish delivery company. The company said the vehicle had left Poland for Berlin earlier in the day but that contact with the driver was lost at around 4pm local time and the firm believed the lorry may have been hijacked.
There has long been concern in Germany that the country's traditional Christmas markets could be a target for a terror attack. German intelligence picked up several indications of an imminent attack on a market in the days leading up to the attack, according to 'Welt' newspaper.
The Breitscheidplatz market, where the attack took place, is particularly vulnerable as it is situated on a pedestrian island between two busy thoroughfares.
Witnesses said the truck had approached from Budapester Strasse, to the north of the market, before veering into the stalls without slowing.
"With the apparent attack on the Christmas market in Berlin, our worst fears have come true," Stephan Mayer of Mrs Merkel's Bavarian sister party, the Christian Social Union, said.
"Now the security concepts at all the Christmas markets in Germany have to be examined."
Since Nice, security experts have warned that it is largely impossible to protect people against this style of attack, in which a lorry is driven into a crowd.
There can be few more quintessentially festive places than a Christmas market, a place decked out in tinsel and holly, where parents and children come to shop and congregate in preparation for one of the Christian calendar's most family orientated holidays.