Claus Hjort Frederiksen has said he could "never imagine" harming Danish interests.
ADVERTISEMENTDenmark's former defence minister has been arrested on suspicion of leaking state secrets
Claus Hjort Frederiksen confirmed on Friday that he was being investigated for "violating the limits of freedom of expression".
Frederiksen -- who served as defence minister from 2016 to 2019 -- is accused of passing on secret information that the country's security or foreign relations depend on. He faces up to 12 years in prison if convicted.
"I have spoken as a member of parliament on a political issue and I have nothing else to say at this time," the Liberal Party MP said in a statement.
"I could never imagine doing anything that would harm Denmark or Danish interests," he added, without giving further details.
The arrest comes days after it was revealed that the former head of Denmark's military intelligence agency was also under investigation.
Lars Findsen has been held in custody for a month on suspicion of leaking confidential documents. Three other former or current employees of Denmark's two intelligence agencies were also initially detained in December.
They are accused of disclosing "highly confidential information from the intelligence services without authorisation".
Findsen has denied any wrongdoing, while the other three suspects have since been released.