rtokens: Bombings are often carried out by criminals to settle scores but the motive in this case was not immediately clear .
pos: JJ NN VBZ VBN IN DT NN IN NN IN CD IN NNP VBZ TO DT NN NN .
tokens: Violent crime has soared since the collapse of communism in 1989 as Bulgaria moves to a market economy .
ltokens: A bomb exploded on Friday at a mosque in the central Bulgarian town of Kazanluk , causing damage but no injuries , state radio said .