German police are on heightened alert after a Tunisian man on Monday plowed a truck into a crowded Christmas market in Berlin, killing 12 people and injuring 56 others.

That's what makes this image that purports to show two female German police officers holding Heckler & Koch MP5 submachine guns -- without magazines -- so provocative. (Click the link; there was a glitch embedding the tweet into this post.)

The Stuttgart-based media outlet Online-Magazin on Friday tweeted the image along with the caption, "Germany: After the #ISIS terrorist attack in #Berlin. Policemen guard Christmas markets with HK-MP5 without magazine and ammo."

It wasn't immediately clear exactly where or when the image was taken, who the officers were, or to which law enforcement unit they belonged. But the idea of patrolling with empty firearms obviously seems dubious.

What do you think? In what scenario does it make sense for police or troops to stand guard with weapons but without magazines -- or ammunition?

Meanwhile, the terrorism suspect, Anis Amri -- whom ISIS claimed as one of its own -- was killed early Friday in a shootout with police in Milan, ending a Europe-wide manhunt, the Associated Press reported. The police officer he shot sustained non-life threatening injuries, according to AP.