Police in Copenhagen have made a number of arrests today over suspicion of preparation for a terrorist attack.
The capital city's police force took coordinated action along with the Danish Security and Intelligence Service (PET) to make the widespread arrests.
It is currently unclear how many people have been detained or the exact nature of the terror threat.
"This is extremely serious," Danish Prime Minister Mette Frederiksen told news agency Ritzau at a meeting with EU ministers in Brussels.
Police in Copenhagen have made a number of arrests (Stock image)WIKICOMMONS"For a number of years now, we have seen that there are people living in Denmark who do not wish us well.
"Who are against our freedom and who are against Danish society, with all that it entails."
He added: "It shows the situation we are in in Denmark. Unfortunately.
"It is absolutely true when both (Denmark's intelligence agencies) say that there is a high risk in Denmark.
"It is of course completely unacceptable in relation to Israel and Gaza, that there is someone who takes a conflict somewhere else in the world into Danish society."
Earlier this month the EU warned there is a "huge risk of terrorist attacks in the European Union" in the lead up to Christmas.
European Home Affairs Commission Ylva Johansson warned that the fallout of the Israel-Hamas war had increased the risk of a coordinated attack.
In September Europol spokesperson Jan Op Gen Oorth warned that Islamist terrorism remains the biggest terror threat in Western Europe and "lone actors are expected to continue to perpetrate most of the terrorist attacks in the EU".
PET has for more than a decade warned against potential attacks, and since 2010 has kept its terrorist alert level at 4 on a scale from 1-5, reflecting a "significant" threat.
In August PET acknowledged that the threat towards Denmark had intensified after anti-Islam activists damaged several copies of the Koran over the summer.
It said at the time there was no reason to increase the alert to the highest level.