Counter - terrorism operations in Europe have uncovered an ISIS sleeper cell in Denmark . Officials fear that it was planning an attack similar to the March suicide bombings in Brussels ( Belgium ) . Four suspects were arrested on 7 April in the capital , Copenhagen , and are believed to have been recruited by extremists operating in Syria . During a related search in the city , ammunitions and weapons were found . The Danish authorities have been on high alert since two people were killed in attacks on a free speech event at a synagogue in the capital in February 2015 . It is believed that more than 125 people have left the country to join ISIS .
Counter-terrorism police in Europe have uncovered an ISIS sleeper cell in Denmark. Officials fear that it was planning an attack similar to the March suicide bombings in Brussels (Belgium). Four suspects were arrested on 7 April in the capital, Copenhagen, and are believed to have been recruited by extremists based in Syria. During a related search in the city, ammunitions and weapons were discovered. The Danish authorities have been on high alert since two people were killed in attacks on a free speech event at a synagogue in the capital in February 2015. It is believed that more than 125 people have left the country to join ISIS.