A blast damaged a police station in Copenhagen on Saturday, the second blast to hit the Danish capital in four days.
No one was injured in the blast outside a small unmanned police station in the Norrebro area near the city center, said Chief Police Inspector Jorgen Bergen Skov.
On Tuesday, one person was slightly injured in an explosion outside the Danish Tax Agency office, in which police said it was a deliberate attack.
Skov said Saturday's blast was also a deliberate act, but it is too early to say whether the two blasts are connected.
"This was not an accident but a deliberate act," Skov said, adding that while the investigation was still underway, nothing suggested that it was related to terror.
"These were attacks on buildings, not people," he said. "But it's too early to say anything about why."
Police were looking for a man seen running from the scene of the blast, he said.
Serious attacks or violence are rare in the Nordic country of 5,7 millions of people who pride themselves on a reputation for security and social tolerance.