Champions League: Manchester City and Chelsea fans involved in ‘violent clashes with police’ ahead of Porto final (VIDEO)

Footage posted online appears to show several clashes between fans of Manchester City and Chelsea, as well as with local police, which are thought to have occurred shortly after local bars in the Portuguese city closed at 10.30pm.

Thousands of fans of both Manchester City and Chelsea have descended on Porto ahead of Saturday's Champions League final, apparently leading to various incidents between opposing supporters, with one clip showing a fracas on a busy city street which prompted cars to blare their horns and locals to scramble for cover.

The chaotic scenes also reportedly saw followers of both English teams engaging in altercations with local police which experts say could lead to a heightened security presence in the city ahead of Saturday's showpiece fixture.

The violence comes days after similar episodes in Gdansk, Poland in which there were skirmishes between Manchester United supporters and locals at bars in the area on the eve of United's penalty shootout defeat to Villarreal on Wednesday.

It is understood that some City supporters were celebrating United's defeat when they got caught up in the melee, with Portuguese outlet Expresso claiming that much of the violence was instigated at the popular Oura Bar.

"That set off pushing and shoving followed by fighting in the street," The Sun quoted an eyewitness as saying.

"Military police had to wade in with batons to break it up."

As of yet there have been no reports of any serious injuries, nor have any arrests been made public.

The Estadio do Dragao is set to host Saturday's final after it was moved from Istanbul for the second consecutive year amid concerns about the spread of Covid-19, with Turkey remaining on the United Kingdom's 'red list' of countries it considers dangerous to travel to. 

Around 16,500 fans are expected to attend the game, a figure which is about 33 percent of the stadium's 50,000 capacity. Fan are obligated to provide a negative PCR test to gain entry to the stadium.

Portuguese public health chiefs, though, have asked English supporters to not spend too much time in the city.

"People who come to the Champions League final will come and return on the same day, with a test done in a bubble situation – that is, on charter flights with trips to a waiting area," explained Minister of State, Mariana Vieira da Silva, earlier this month.

"Then they will go to the stadium and then to the airport, being in national territory less than 24 hours, in a bubble stay and with mandatory tests done, in principle, before getting on the plane."