A 16-year-old Syrian refugee went on trial in Germany on Monday (February 20th) on charges of planning a bomb attack on behalf of the "Islamic State of Iraq and the Levant" (ISIL), AFP reported.

The youngster was arrested at an asylum shelter in the western city of Cologne in September, with the authorities describing him as a "serious threat".

Police at the time said the suspect's mobile phone showed he had been in touch with an ISIL contact abroad and had expressed willingness to carry out an attack.

Investigators found online chat messages on the phone that included "concrete instructions" for building an explosive device, prosecutors added.

Officers searching his accommodation discovered items that could be used to prepare a bomb, DPA national news agency reported, citing the charge sheet.

The trial at the district court in Cologne, scheduled to last until March 20th, is being held behind closed doors because the accused is a legal minor.

If convicted, he faces a maximum sentence of five years' detention under the juvenile penal code.

He was brought to police attention after residents and employees at the refugee shelter where he was staying voiced concerns that he had been radicalised, as did a local mosque.