The Football Association has called the fans involved in disturbances in Porto an "embarrassment" to the England team.
The Three Lions' preparations for Thursday's Nations League semi-final with Holland in Guimaraes have been overshadowed by another night of disruption in nearby Porto.
England supporters clashed with Portuguese police and were seen hurling bottles, prompting some local families watching the hosts' match against Switzerland in a fan zone to flee with their crying children.
'England 'til I die' filled the air along with more unsavoury chants - just the latest embarrassing chapter when the Three Lions travel abroad, with trouble marring last year's trips to Amsterdam and Seville.
An FA spokesperson said: "The FA strongly condemns the scenes witnessed in Porto overnight. Anyone responsible for these disturbances cannot be seen as true England supporters and are not welcome in football.
"They are an embarrassment to the team and the thousands of well-behaved fans who follow England in the right way. We are liaising with the UK Football Policing Unit."
Just last week the FA launched a video called 'Don't Be That Idiot', highlighting the embarrassment unacceptable behaviour can cause.
That call appears to have fallen on deaf ears and Press Association Sport has seen the FA's message to England Supporters Travel Club members on its Facebook group.
The message read: "The FA will always investigate incidences of inappropriate behaviour before, during or after an England match.
"We know that the overwhelming majority of England fans are having a great time in Portugal and acting appropriately - we'd like to thank those for following England the 'right way' and hope you all enjoy the match tonight."
Members have been reminded of the ways that they can report incidents in confidence but warned them to "please be careful if you are taking any photos of those involved and don't put your safety at risk".
It is a sad state of affairs and also brought condemnation from Deputy Chief Constable Mark Roberts, National Police Chiefs' Council football policing lead.
"This is the second evening in a row where disorder has occurred in Porto," he said on Wednesday. "Last night there were issues outside a bar, where bottles were thrown and minor damage was caused.
"It is completely unacceptable. The behaviour we are witnessing is incredibly disappointing and again I would point fans towards the recent video from the FA - 'Don't be that idiot'. The behaviour of a small number of the England fans out here continues to tarnish the reputation of the genuine fans who are simply trying to enjoy the football."