On Sunday, a leftist group in Germany posted a statement online claiming to have set fires several fires and vandalized the Hamburg exhibition center less than two weeks before it hosts the next summit of the Organization for Security and Co-operation in Europe (OSCE).

"We decided to do this act of destruction because we refuse to accept the exhibition hall - which considers itself a global trade fair - and likewise reject the meetings of rulers there," the statement read.

The group admitted to setting fires, as well as using rocks, paint and hammers to vandalize one of the trade fair's glass entrances.

The group opposes the ministerial OSCE meeting, as well as the next G20 summit, which is set to be held in the same building next summer.

Police said they believed the statement to be valid.

Late on Saturday, multiple fires were set at the southern entrance of the building while two barricades blazed in the street, a spokesman for the fire department said.

Witnesses said about 30 to 50 people wearing masks were responsible. The vandals fled before police arrived.

Officers found that multiple garbage containers, a motorcycle and part of the glass at the entrance had been set on fire.

Police also said the suspects scattered nails and spikes on the road while they fled, the German public broadcaster NDR reported.

The damage sustained at the structure's entrance was "substantial," but there were no reports of injuries, the fire department spokesman said.

The OSCE meeting of foreign ministers is set to take place at the facility on December 8 and 9. The G20 meeting of industrialized states in 2017 is expected to include the presidents of the United States, China and Russia.

Police expect that massive protests will take place at both events.

rs/mkg (AP, AFP, dpa)