The U.S. Ambassador in Albania says fighting organized crime remains the Western Balkan country's biggest and most difficult challenge.

Speaking Monday at the Magistrates School that annually produces a small number of judges and prosecutors, Donald Lu said that "until the big fish are arrested, prosecuted and go to jail, the cannabis will return, judges will be bribed, and government officials will be corrupted."

Fighting organized crime, illegal drugs and trafficking of weapons and people have been among the international community's concerns for post-communist Albania, which is expecting to start membership negotiations with the European Union next year.

Last year the parliament passed legal reforms that will restructure Albania's flawed justice system to ensure that judges and prosecutors are independent from politics, and to root out bribery.