Four people suspected of having "enlisted" in the Islamic State group with the intention to commit terror have been arrested, Danish police said.
All four suspects, arrested on Thursday in Copenhagen and its suburbs, are suspected of violating Danish laws by joining a terrorist organisation.
Police spokesman Poul Kjeldsen said arms and munitions had been found in one location but it was not immediately clear whether that could be connected to the arrests.
Mr Kjeldsen said he could not exclude the possibility of more arrests as the investigation continues.
Police declined to disclose further details, saying the prosecution would ask for closed doors at a pre-trial detention hearing on Friday, which would bar the publication of details.
Mr Kjeldsen said the four suspects had been identified through "close cooperation" between Denmark's intelligence agency and the police in the Danish capital.
Justice Minister Soren Pind said "it was too early to say" what the suspects' plans were.
"We are now harvesting the fruits of our thorough efforts... to stop foreign fighters," Mr Pind said in a television interview.
About 60 Danish nationals have returned from Syria where they have fought alongside Islamic State members. It was unclear whether the four suspects had been in Syria.
The case was not immediately believed to be linked to the arrest of a 20-year-old man in Sweden who has been was charged with preparing to a make a suicide bomb.