Newcastle United said French police "indiscriminately assaulted" several of their supporters and used pepper spray, batons and shields while escorting visiting fans from the stadium after Tuesday's 2-1 Champions League loss at Olympique de Marseille.
The Premier League side said on Thursday they would formally raise their concerns with UEFA, the host club and French police over the "unnecessary and disproportionate" force their fans were subjected to.
"Plans were in place to move 500 supporters at a time... once the first group of supporters was released, the police began using unnecessary and disproportionate force to stop the remainder of our fans from moving any further," Newcastle said in a statement.
"This was actioned through a combination of pepper spray, batons and shields, with numerous supporters being indiscriminately assaulted by the police.
"Many supporters were visibly distressed, particularly in the upper concourse area of the away sector, where crushing became apparent."
Marseille said the arrangements for away supporters were planned well in advance in coordination with the Prefecture of Police, UEFA and Newcastle, adding that the measures complied with UEFA standards and were implemented without issues.
"No specific incidents or alerts were reported to it (club) by Newcastle United FC during the evening of the match, either by their representatives present at the stadium or in the hours following the match," Marseille said in a statement.
"The feedback sent to our department by UEFA after the match attests to the quality of the measures put in place and their successful operational implementation ... the club cannot accept that its responsibility should be wrongly called into question."
Marseille police said in a statement that they maintained a friendly attitude with visiting Newcastle fans, but in one instance, a crowd surge prompted riot police to intervene.
"At one point, towards the end of the operation, in the visitors' section, a crowd surge required the intervention of the CRS riot police, one of whom made very limited use of tear gas, which caused discomfort to around 20 fans for a few minutes," the police said.
"Apart from this incident, no force was used and the operation went smoothly. No injuries or complaints were reported following this event."
Fans leaving the stadium shared their anger and frustration with Newcastle staff, the British club added.
"We will be calling on UEFA, Olympique de Marseille and local authorities to formally investigate this matter to ensure lessons are learned and this behaviour is not repeated," Newcastle said.
"We are continuing to liaise with the United Kingdom Football Policing Unit (UKFPU) as we gather evidence on behalf of our supporters."
Newcastle are 11th in the Champions League, with nine points from five matches. They will visit Bayer Leverkusen on 10 December.

