(CNN) -- An explosion blew out windows at a court in the Netherlands early Wednesday, police in Amsterdam confirmed.
The explosion in a staircase of the Amsterdam District Court building occurred at about 2:30 a.m. local time (8:30 p.m ET Tuesday), said a police spokeswoman, who cannot be named in line with department policy.
Police are now searching for two people seen running from the building, she said. She declined to comment on whether any threats had been made against the court.
"There have been a lot of different reports about what happened, but we can't give any details about the explosives or how it happened as our investigation is at very early stages," she added.
The court building is in the southern part of the city.
CNN's Per Nyberg contributed to this report.