Authorities in Morocco have reported that they warned their German counterparts against an imminent terrorist threat twice before Monday's deadly market attack in Berlin.

Sources say the Moroccan security services warned Germany on September 19th and October 11th.

The source revealed that the main suspect, identified as Tunisian national Anis Amri, pledged allegiance to the Islamic State group about a year ago, and had been plotting the attack with an ISIL-linked Russian and several other Moroccans since June. 

Also, Spain's intelligence department said that a Spanish national had possibly contacted Amri online before the attack. Authorities say they are deciding whether to take action after further investigations.