Germany's main opposition leader demanded a sweeping overhaul of migration policy and permanent border controls on Thursday, a day after an Afghan asylum seeker was arrested for a deadly knife attack targeting children weeks before federal elections.

German police say two people, including a two-year-old boy, were killed and two others were severely injured in a stabbing attack in Bavaria.

In a tragic incident in Aschaffenburg, Germany, two individuals, including a young Moroccan child, lost their lives in a knife attack perpetrated by an Afghan man. The attack also left two others injured.

A 28-year-old man from Afghanistan has been arrested following a knife attack in a park in the German city of Aschaffenburg on Wednesday in which two people were killed, including a toddler, police said.