June 24 (UPI) -- An explosion destroyed an apartment building in Germany last Saturday, injuring at least 25 people, including five of them seriously, according to emergency services officials.
The blast rocked the multi-story building in the western Germany city of Wuppertal just before midnight Saturday, officials said.
An investigation is underway to determine the cause of the blast.
"How this came to pass and what the background is, that remains completely unclear," a police official said.
The scene was described as a "picture of devastation" by police.
The explosion created a large hole in the building. Flats on both side were danger of collapse and vehicles were crushed.
Firefighters struggled to put out flames because some of the building kept collapsing and several small fires broke out inside. Engineers were stabilizing the partially collapsed building.
"It can currently not be ruled out that there are still other people in the building," police said Sunday morning. "The rescue efforts are ongoing."
Some residents escaped and others needed to be rescued by firefighters.
The explosion was so strong, people in surrounding homes ran out into the street.