Domestic intelligence PET's Centre of Terrorism Analysis (CTA) says that fighters returning from the Syrian Civil War pose a significant risk to domestic safety.

A new report from CTA assesses that at least 80 people since 2012 have gone to Syria to fight in that country's ongoing civil war, and that at least seven Danish nationals have died fighting there. A significant number of the fighters have learned military skills that they could potentially use to plan acts of terrorism back home.

"We have found that some people among the Danish fighters in Syria have joined groups that share al-Qaeda's global militant Islamist ideology," the head of CTA, Søren Jensen, said. "It is the combination of the military skills they achieve by participating in the Syrian conflict with the militant Islamist ideology that may lead to an increased terror threat against Denmark and Danish interests abroad."

The agency previously estimated the number of Danes who have fought in Syria to be at least 65.

READ MORE: Two Danes allegedly die fighting in Syria

Fighters face prosecution

PET and the Justice Ministry have warned Danish Muslims fighting in Syria that they can face prosecution upon returning to Denmark.

So far none of the former fighters have been charged, but the head of PET, Jakob Scharf, said the agency may have soon collected enough evidence to carry out trials against some of them.

READ MORE: Government to crack down on Syrian fighters

"We are looking for cases where we can present the evidence we need to prove that the fighters have committed criminal activities," Scharf told DR Nyheder. "I can't leave out the option that we can present the necessary evidence."

PET also stated that foreign fighters from other European countries may pose a threat against national security. 

Jihadists and gang leaders
Some of the Danish fighters in Syria have been featured heavily in the media. Concerns mounted after jihadist Abu Khattab began posting recruiting videos on YouTube, one of which showed Khattab and three other fighters shooting targets at pictures of notable Danish Islam critics.

READ MORE: Gang leader in Syria documentary wanted for assault

Among the fighters were also former gang leader Abderozzak Benarabe, known as Store A (Big A), who appeared in a documentary on public broadcaster DR2. PET interrogated the gang leader when he first returned to Denmark, but he hasn’t faced any terrorism charges.

"It is a new thing for us that so many people with a criminal background go there," Jensen of CTA told DR Nyheder. "We suspect that some of them simply do it for the excitement."