CSKA Sofia coach knocked out by snowball

On a snow-bound day when police detained 57 suspected football hooligans before leaders CSKA's 3-0 win, Mladenov was hit in the head by the snowball in the early stages of the game and collapsed on to the athletics track surrounding the pitch before coming round.

"They hit me with a snowball and I lost consciousness," Mladenov complained to reporters after he had recovered. "It's not the first, second or third Levski offence.

"They should throw them out of the group! Tomorrow, someone could die."

Police detained the suspected hooligans before the 137th "eternal derby", as the fixture between the two most popular clubs in Bulgaria is known, was marred by crowd trouble.

Bulgaria's interior ministry said in a statement most had been held on their way to the Vasil Levski national stadium in the centre of Sofia for carrying prohibited objects, including missiles, torches, knives, a sword and a machete.

Still, it did not stop trouble at the match, which was interrupted for several minutes after Mladenov had been hit as the two sets of coaching staff and a dozen players became involved in a skirmish.

Later, after CSKA's third goal, Levski fans broke the safety fences and more than several dozen invaded the athletics track, forcing more than a hundred policemen to bar them from making their way to the pitch.

The fixture has a long history of crowd violence. A 30-year-old man was killed by a bomb in 2000 and hooliganism and arrests have been rife since then.

Extra police officers were on hand to monitor the fans in the city centre and around the stadium.

CSKA had criticised hosts Levski for poor organisation and asked the match delegate and referee to postpone the match due to the heavy snowfall and snow-bound pitch but the officials turned down the appeal.

On the pitch, it turned out to be CSKA's sixth successive win over Levski, moving them 10 points clear at the top of the table with Mladenov's men aiming to win the title for the first time since 2008.

Lively Romanian striker Sergiu Bus scored in first half stoppage time to take his tally to eight goals this season, after setting up Portuguese winger Toni Silva's opener. Substitute Boris Galchev sealed victory with a late strike.

The 31-times Bulgarian champions CSKA top the standings with 32 points from 13 matches. Levski are fourth on 21, only a point behind champions Ludogorets, who are second.