Supporters of Israeli soccer team Maccabi Tel Aviv were targeted for beatings by groups of thugs in the early hours of Friday following a match with Amsterdam's Ajax, the city's mayor Femke Halsema has said.
Among dozens of Israeli supporters who were chased and assaulted, five suffered injuries needing hospital treatment, police said. In all 63 suspects have been arrested and authorities promised an investigation, as politicians within the country and beyond expressed their condemnation.
Here is a closer look at how the situation escalated.
Tension began to build on Wednesday as some of the 3,000 visiting Maccabi supporters had minor altercations back and forth with locals including taxi drivers and Ajax supporters in the city centre, police said.
A police report said groups of Maccabi supporters burned a Palestinian flag on Dam square, pulled another down from a nearby building and vandalised a taxi.
After a call went out on social media, angry Muslim taxi drivers gathered outside a casino where a group of 400 Maccabi supporters were gathered, and police intervened amid skirmishes.
Dutch media have reported on videos purportedly showing the beating of a Muslim taxi driver and a group of youths yelling anti-Semitic slurs at a person in a canal said to be a Maccabi supporter who was pushed in.
Reuters was unable to confirm those incidents took place as portrayed.
On the day of the match, Maccabi supporters were filmed chanting anti-Arab slogans in front of the National Monument on Amsterdam's central Dam square, including "Fuck you Palestine", in videos verified by Reuters.
Police guarded the perimeter but fights around the fringes were reported.
Dutch pro-Palestinian groups planned a demonstration outside the stadium during the game, arguing that the match should have been cancelled because of alleged Israeli war crimes in Gaza. Israel denies war crimes, saying it is defending itself and blaming Hamas for civilian deaths, which the militants reject.
Dutch authorities were aware of anger over the war in Gaza, but saw no reason to cancel the match. The relationship between supporters -- the usual source of football violence -- is generally good between the two teams, Halsema said on Friday.
Ajax has strong Jewish associations, and fans sometimes carry Star of David flags to matches; it also has many Muslim supporters.
Less than 1% of Amsterdam's population is Jewish following the Holocaust, while around 15% is Muslim, mostly second and first generation immigrants from North Africa and the Middle East.
The conservative Dutch government has vowed to implement Europe's strictest measures to limit immigration and reject asylum-seekers.
Anti-Semitic incidents have surged in the Netherlands since Israel launched its assault on the Palestinian enclave after the Hamas attacks on Israel in October last year, with many Jewish organisations and schools reporting threats and hate mail.
With a confrontation between protesters and football supporters seen as the biggest security threat, the mayor moved the demonstration against the match to a remote location.
Ajax's most hardcore group of supporters, known as the F-Side, had said politics and football should be kept separate and that they would "intervene if necessary" if it went ahead at the ground.
Riot police at the stadium kept opposing groups apart and few incidents were reported when the match ended around 11 p.m.
However in the city centre, around midnight, security fell apart.
Calls to target returning Maccabi supporters began circulating on Dutch messaging groups, leading to what mayor Halsema described as "anti-Semitic hit and run assaults".
Police used to dispersing football mobs could not easily stop smaller, highly mobile groups of attackers with no obvious club allegiance.
Police said they collected around 200 Maccabi fans on Dam square to protect them and escort them back to their hotels, but many were assaulted elsewhere in town, with perpetrators quickly fleeing on motor scooters.
Films on social media and verified by Reuters showed groups attacking Israelis, kicking victims after they had fallen, throwing fireworks and in one instance shouting "That's Palestine. That's Gaza, mother-fucker"..."now you know how it feels."
Of the 63 people detained, most were later released pending charges.
Amsterdam banned demonstrations through the weekend and gave police emergency stop-and-search powers.
