A Muslim convert wearing a full burka has attacked two police officers with a knife as they entered her apartment in the western city of Mülheim, Germany. A search of the property turned up material in support of Islamic State.

Police were called to check on the 53-year-old after receiving a phone call early Sunday morning from neighbours who said she was flinging furniture, including a lamp, chairs, and books, out of the window of her fifth-floor apartment.

The woman refused to open the front door of the apartment, forcing officers to break it down. Once inside, they were attacked by the knife-wielding Islamic convert, who was shouting “Allahu Akbar”, police spokesman Marco Ueberbach reported.

The fully-veiled woman was subdued after officers used pepper spray on her, and threatened to draw their firearms. Neither police officer was injured in the scuffle, but the woman was later taken to a psychiatric hospital.

Police found flags and literature in support of Islamic State in a search of the property. The woman “is already known to police for radical Islam-motivated threats”, Ueberbach informed reporters.

Last month, the Islamist terror group urged supporters to “overcome their squeamishness” and carry out a “campaign of knife attacks”. Released by the organisation’s Al-Hayat media centre, the October edition of Islamic State’s Rumiyah (Rome) magazine said would-be jihadists should target random victims “in quiet neighbourhoods.

Germany has experienced a string of attacks linked to the Islamic terror group since more than a million, mostly Muslim, migrants entered the country last year.

Islamic State’s news agency Amaq claimed responsibility for a knife attack two weeks ago in Hamburg that left a 16-year-old boy dead.

In September, an Iraqi asylum seeker linked to al-Qaeda was shot dead after stabbing a German policewoman in the neck during an attack in west Berlin.

Another police officer was left seriously injured in February by a 15-year-old girl of Moroccan origin who was acting “on behalf of the Islamic State”.

Four months later, in July, an axe-wielding Afghan rampaged through a train near the city of Würzburg, leaving four people injured before he was shot dead by police.

Then just five days after that, more than a dozen Germans were wounded when a 27-year-old Syrian launched a suicide bomb attack on a bar, shortly after pledging allegiance to Islamic State.