* Five more held from second tier rivals (Adds detail, BFU statement)
SOFIA, Dec 13 (Reuters) - Police have arrested six players from Bulgarian first division Chernomorets Burgas and five from second tier Neftochimik, their city rivals, for questioning in an investigation into alleged match-fixing.
"I can confirm 11 players were arrested for match-fixing," a spokeswoman for the interior ministry said on Thursday. "All of them are Bulgarians."
She added the initial investigation was triggered two months ago by signals of illegal betting but refused to disclose more details.
Local media reported that Chernomorets's Rumen Trifonov and team mates Preslav Yordanov and Daniel Mladenov were taken in handcuffs from the police station in Burgas and driven to an undisclosed destination.
Interior Minister Tsvetan Tsvetanov said four of the 11 footballers would probably be charged.
"Our coach Dimitar Dimitrov told me a few players had been arrested," said club owner Mitko Sabev. "We're sure they didn't manipulate Chernomorets games."
Neftochimik coach Dimcho Nenov said he was not aware any of his footballers had been questioned and confirmed that all the players took part in Thursday's training session.
Chernomorets are sixth in the league with 27 points from 15 games. Neftochimik are top of the second division with 28 points from 13 matches.
"We support the interior ministry's decisive actions in the fight against organised crime and all the occurrences that threaten the basic principle of football - fair play," the Bulgarian Football Union (BFU) said in a statement.
Media reports of widespread match-fixing and corruption have been rife in the Balkan country for years but no one has been brought to trial and the European Commission has criticised the authorities for doing little to fight the problem.
In September, Bulgaria's prosecutor opened an investigation into claims of match-fixing in four domestic games this season.
The first documented manipulated game in the country took place in 1949 when Levski Sofia and city neighbours Akademik drew 1-1 in order that CSKA, Levski's bitter rivals, would be relegated to the second division. (Reporting by Angel Krasimirov; editing by John Mehaffey and Tony Jimenez)