ATHENS – A terrorist attack claimed by an Islamic State offshoot in a Moscow concert hall that killed 139 people has sparked fears it will strike elsewhere, Greece’s National Intelligence Service EYP stepping up checks.

That’s being done at entry points on the border where refugees and migrants cross in hopes of getting asylum, and detention centers where they are being will also be monitored for radicalists, said Kathimerini.

ISIS-K claimed responsibility and said it was in retaliation for Russia suppressing Muslims in the Caucasus region, the incident coming during Israel’s ongoing invasion of the Gaza Strip earlier also putting Greece on alert.

Greece’s New Democracy government backs Israel, which is hunting Hamas terrorists who killed more than 1200 people in raids on Oct. 7, 2023 but there are concerns about the rising death toll of Palestinians trapped in Gaza.

Greece is trying to walk a fine line between backing Israel and calling for caution over civilians in Gaza, a Muslim population. The Moscow attack has roiled worries of extremist action in Europe too.

Greek police are said to be vigilant and had earlier been looking at refugee and migrant detention camps for radicalists hiding among those seeking asylum, with Greece’s right-wing anxious of possible attacks in the country.

The Islamic State of Khorasan or ISIS-K group has recently attempted to expand its activities from Central Asia, Uzbekistan, Tajikistan or Kyrgyzstan to Europe, and worries that Americans could be at risk.

Russian President Vladimir Putin failed to heed a warning from the CIA of a likely imminent attack in public venues, dismissing it as fear-mongering, but the US told Americans in Russia to be cautious.

US officials said ISIS-K is capable of going after targets of US and Western interest and the alarm in Greece comes as spring has brought warmer weather and tourists are beginning to come in bigger numbers.