This week, police and security forces in Finland and Sweden have announced that dozens of those countries' citizens are fighting with the Islamic State (IS) group in Syria and Iraq.
According to Helsinki Police Chief Inspector Jari Taponen, around 50 people from Finland, 76 percent of whom are Finnish passport holders and "almost 20" of whom are ethnic Finns, have gone to IS-controlled areas in Syria and Iraq.
Taponen told Finnish TV channel Yle TV1 on January 22 that the major priority for Finnish security forces is to "try to prevent travel to the war zone."
According to Taponen, the Finnish Security Intelligence Service, Supo, believes that as many as eight people from Finland have been killed fighting alongside IS.
Radicalism among young female converts to Islam in Finland has increased in recent months, he said, adding that most of those who have joined IS are from the Helsinki region.
Like other European nations, Finland is concerned about the possible threat of blowback from its nationals who return home after fighting with IS in Syria.
Taponen said that the Helsinki police plans to start a mentoring program to prevent radicalization, and said that the key to dealing with returning IS militants is to reintegrate the individual back into society."
In neighboring Sweden, that country's Security Service, Sapo, confirmed that at least 100 Swedes have joined the IS group.
Sapo head Anders Thornberg told the TT news agency this week that his organization had seen "an increasing number of young Swedes traveling to Syria where they go and get training in training camps, handle explosives, handle weapons."
The number of confirmed cases of Swedes fighting with militants in Syria has increased from 92 last week to 100, Thornberg said.
"They bought a car in Sweden and drove all the way to Shaam [Syria] with it."
One documented case of a Swedish national fighting -- and dying -- for IS in Syria has come from the online diary of a British woman, Umm Khattab al-Britaniyyaa, who says she was married to a Swedish IS militant until his death in October in Kobani.
In her diary, Umm Khatab writes that her husband, who called himself Abu Khattab al-Swedi ["The Swede"], had come to Syria from Sweden with his best friend, Abu Uthman al-Afghani ["The Afghan"].
"They bought a car together in Sweden and drove all the way to shaam [Syria] with it," Umm Khatab wrote of her husband and Afghani.
While both Swedi and Afghani came to Syria from Sweden, the former's chosen name suggests that he is most likely to be an ethnic Swede, while the latter is an ethnic Afghan. Sweden is home to several thousand Afghan refugees, though there are reports of the country rejecting the cases of Afghan asylum seekers.
Umm Khatab provides some details about her husband's activities in Syria.
He "always put jihad first," she wrote, and spent most of his time away from home either fighting or guarding the front lines.
Swedi's wish was to become a "martyr" and die in battle, Umm Khatab disclosed.
"I knew how much he wanted [martyrdom] so now that he has attained what he was seeking for which is one of the best things how can I grieve," she wrote.
Umm Khatab also admitted that, when speaking of his hoped-for death, Swedi had told her that "although I won't be here to take care of you know Allah is the best of providers."
In late September, Swedi was sent to Kobani in northern Syria with a group of militants, Umm Khatab recalls in her diary.
Swedi fought in Kobani for two weeks before returning home for a day on October 9, "because he had a slight injury."
On October 18, 10 days before his death, Swedi sent a "voicenote" to Umm Khattab saying "it's either victory or [martyrdom]."
-- Joanna Paraszczuk