Danish police have arrested seven suspected terrorists, the country's security intelligence service says.
The suspects, believed to be all men aged between 18 and 33, were picked up during overnight raids in Odense, Denmark's third largest city.
The country's Justice Minister, Lene Espersen, said it was likely they were planning an attack in Denmark.
The men had been under surveillance for months and were detained on suspicion of planning terror acts.
Two others who were arrested at the same time have been released.
All seven are due in court later and are being held under anti-terror laws introduced after the 11 September 2001 attacks on the US.
Ms Espersen said: "The clues police found indicate that they were very likely planning an attack somewhere in Denmark.
"It was the most serious matter I have had in my time as justice minister. Police went in and stopped the group as it was preparing an attack."
'No unnecessary risk'
Lars Findsen, head of the Danish Security Intelligence Service (Pet), said in a statement that the arrests happened in the city's suburb of Vollsmose.
He said the suspects "had acquired material... to build explosives in connection with the preparation of a terror act".
Mr Findsen did not reveal any planned target of the attack and said it was hard to evaluate how far the suspects had got in their preparations.
"With the general terror situation, the Danish Security Intelligence Service didn't want to run any unnecessary risk."
The arrests would not prompt Denmark to raise its terror alert, Mr Findsen added.