Missiles were thrown at police as Legia fans were held in a coach park near Villa Park ahead of their side's Europa Conference League fixture against Aston Villa, which the hosts won 2-1.

Villa have made an official complaint to UEFA regarding the behaviour of the Legia supporters.

"The lack of cooperation and prevarication from Legia Warsaw officials prior to the match was entirely unacceptable and deeply disappointing," said Chris Heck, president of business operations at Aston Villa.

"This behaviour increased the danger that West Midlands Police officers and our own fans were subjected to before the game and the scenes of disorder from the Legia fans have no place in modern football or civilised society."

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The match did start on time but no Legia fans were allowed into the stadium ahead of kick-off. Legia accused Villa of reneging on their agreement regarding the away ticket allocation, but Villa said the decision was made over safety concerns.

After the match, West Midlands Police said in a statement: "We were faced with disgusting and highly dangerous scenes as trouble flared ahead of the fixture between Aston Villa and Legia Warsaw.

"We had a significant policing presence in place because of safety concerns. This stemmed from visiting fans having been involved in previous matchday disorder.

"The disorder is believed to have sparked when tickets were not distributed by the away club to supporters outside the ground, as had been anticipated.

"During the disorder four officers were injured - with one taken to hospital - along with two police horses and two police dogs as missiles including flares were thrown towards them. Thankfully their injuries are not believed to be serious."

Chief inspector Tim Robinson, the match commander, added: "This should have been a great evening of football which was enjoyed by fans from both clubs.

"Unfortunately, there were appalling scenes which saw away fans dangerously throw flares and other missiles at our officers.

"We were there to help keep people safe, yet officers' own safety was put at risk because of the deplorable actions of others.

"Due to the extreme violence, there was no other choice but to prevent away fans entering the stadium. The safety of everyone is our priority and clearly we had no other option.

"There can never be a place for such appalling behaviour and this is something ourselves and the wider community should never have to experience."

During the match, Villa released a statement revealing requests to the Polish club before the tie for help in preventing ticketless fans from travelling went unanswered.

Villa said: "The UK safety authorities, UEFA and Aston Villa, communicated on November 2 that the ticket allocation for away fans for this fixture would be reduced to 1,002 on the advice of safety authorities as a result of previous large-scale disorder caused by Legia fans last month at AZ Alkmaar.

"A number of Dutch police officers were injured during that disorder. As a consequence, UEFA banned Legia supporters from travelling to Mostar for their game against HSK Zrinjski.

"In spite of numerous requests for cooperation from Legia Warsaw concerning their travelling supporters, especially in the last two days, no assistance on the serious safety matter of away fans attending Villa Park was forthcoming from the visiting club.

"The club has repeatedly, including [Thursday] morning, raised concerns in conjunction with UEFA and all the relevant authorities to Legia that ticketless away supporters were attempting to attend Villa Park."

Villa said Legia fans "engaged in planned and systematic violent acts against West Midlands Police officers" about an hour before kick-off.

The club added: "Aston Villa strongly condemns the behaviour of those visiting supporters and would like to thank West Midlands Police for their professionalism in very difficult circumstances."

In its own pre-game statement, the Polish side accused Villa of restricting access to their fans in a move it called "counterproductive and baseless".

It said senior executives, including the club's owner, made the decision to boycott the game in response to the move.

The statement added the two clubs agreed an allocation of 1,700 tickets for away supporters on September 21 but Legia claimed that number was slashed by 50 per cent on November 20, adding Aston Villa "blatantly disregarded the prior agreements".

As well as the violent clashes, Villa stewards also removed several people believed to be away supporters from the home stands while footage on social media appeared to show objects being thrown into the stadium from outside.

UEFA strongly condemned the violence and said it is gathering all official reports from the game before deciding on potential next steps.