Berlin, May 21 (RHC)-- Germany's Federal Criminal Police Office has expressed concern over an increase in the number of arson attacks on refugee shelters amid growing anti-asylum seeker sentiment in the European country.

Holger Muench, head of the police office known by its German acronym BKA, told the Funke newspaper group that 45 arson attacks have been carried out on refugee camps so far this year. The official also voiced concern about a surge in verbal violence and online hate crimes against refugees in Germany.

He warned that "criminal or even terrorist structures" could arise due to the anti-refugee sentiment, adding that the German police were taking this threat "very seriously."

In 2015, 92 arson fires were reported at accommodation centers for refugees, compared with only six recorded in 2014, according to the latest BKA figures.

Germany opened its borders to the refugees last summer with a welcoming mood, but it gradually shifted away from the policy.

As one of the most popular destinations for refugees, the Western European state registered about 1.1 million refugees between January and December 2015.

Europe is facing an unprecedented influx of refugees, most of whom are fleeing conflict zones in Africa and the Middle East, particularly Syria.

Many blame major European powers for the unprecedented exodus, saying their policies have led to a surge in terrorism and war in the violence-hit regions, forcing more people out of their homes.