Two African brothers who originally migrated from Somalia have been arrested on suspicion of plotting a terror attack, Denmark's security service has said

The African men, aged 18 and 23, were suspected of being in the process of preparing an act of terror after being overheard talking about methods, targets and different weapon types, the Danish Security and Intelligence Service said. The agency, known by its Danish acronym PET, said that the brothers have been arrested — one in the western city of Aarhus and the other as he arrived by plane at Copenhagen's international airport. The suspects have Danish citizenship but are of Somali origin who have lived in Denmark for 16 years, the agency said. One of the African men had been at a training camp in Somalia run by the Islamist militant group al-Shabab, which has links to al Qaeda, PET said. The African men were charged with receiving training with the aim of committing an act of terror, in what the agency said are the first known terror-trained suspects in Denmark. The Scandinavian country has been in the cross-hairs of Islamist terror groups after the publication of newspaper cartoons depicting the Prophet Muhammad in 2005. A Somali man living in Denmark was convicted of terrorism and sentenced to 10 years in prison after breaking into the home of one of the cartoonists with an ax in 2010. In 2011, a Chechen-born Muslim was sentenced to 12 years in prison for preparing a letter bomb that exploded as he was assembling it in a Copenhagen hotel in 2010.