COPENHAGEN (Reuters) - Denmark faces a "significant" threat from radicalized Muslim citizens returning home from Syria and Iraq where at least 110 people have gone to fight with jihadist groups like Islamic State, the Danish intelligence service (PET) said on Friday.
It said at least 16 of those who had gone to Syria and Iraq from Denmark had been killed in fighting and that about half of the more than 100 who had traveled there had since come home.
Denmark is among a range of Western European countries struggling to stop the radicalization of young Muslim citizens and deter them from becoming jihadists in Syria or Iraq, fearing they might return to plot attacks on home soil.
In addition, Denmark has sent seven F-16 fighter jets to Iraq as part of the U.S. coalition now conducting air strikes on Islamic State, raising fear of reprisals at home.
"(The agency) assesses that the number of individuals traveling from Denmark to the conflict zone totals at least 110, but that the number may be higher," the PET said, adding that a small number of women had traveled there too.
None of those returning have been prosecuted because traveling to Syria and Iraq is not illegal but they are being monitored by the PET, a security source said. Some of those back have traveled to the regions many times, PET's report said.
With a population of 5.7 million, the number of Danish citizens traveling to join hardline Islamist groups in Syria and Iraq is one of the highest per capita in Europe. Thousands of people with Western passports have been fighting there.
Muslims account for up to 7 percent of the population although estimates vary.
Denmark drew violent Muslim protests in 2005 after the publication by a Danish newspaper of cartoons portraying the Prophet Mohammad. The protests spread worldwide and caused a number of deaths.
But there has been no major attack in Denmark in the modern era, unlike in larger European states like France and Britain. A planned attack on the newspaper that published the Mohammad cartoons was thwarted in 2010.
Public security in Denmark remains strikingly relaxed compared to other European states. Passports are often only barely checked at airports even for travel outside the European Union's Schengen border-free zone, while visitors can stroll through parliament at will, albeit after a metal detector scan.
(Reporting by Sabina Zawadzki; Editing by Mark Heinrich)