Police in the Danish capital said two predawn explosions took place Wednesday in the vicinity of the Israeli Embassy in Copenhagen, prompting the nearby Jewish school to close for the day.
Police said no one had been injured and they were investigating whether there was a link between the blasts and the Israeli diplomatic mission, which is close by several other embassies.
They declined to say whether anyone had been arrested.
Heavily armed officers, search dogs and forensic teams were inspecting the area which had been cordoned off.
Copenhagen's Jewish school, Carolineskolen, which is just down the street from the embassy, was already due to remain closed on Thursday and Friday for the Jewish New Year holidays, Michael Rachlin, a spokesperson for Denmark's Jewish community told The Associated Press.
There will also be extra security around the main synagogue in downtown Copenhagen, the Jewish community said in a statement. Community chairman Henrik Goldstein wrote that he “would like to encourage people to be aware when moving in public spaces.”
“And be critical of what you hear on social media and rumours,” he wrote, adding that “there is no reason to refrain from participating in Jewish life.”
Police refused to give details about the intensity of the reported blasts or the damage they may have caused.
On Tuesday night, the area around the Israeli Embassy in Stockholm was also closed off after a loud bang was reported. Police later announced that findings from the scene indicated that the embassy was hit by bullets. No one has been arrested, they said.