In this first poster, the scene location appears to be in the vicinity of the American International Building (70 Pine St.) in Lower Manhattan, though the logos on the police cruiser is for an unknown police force. 

The English message reads as follows:

THINK OF WHAT HAPPENED TO THE
SOLDIERS OF YOUR COUNTRY, WHICH
WILL SOON HAPPEN IN YOUR OWN HOME

OUR BURNING FLAME AND SHARP KNIVES WILL REACH YOU

The Arabic calligraphy at the bottom is a direct translation of the English words "JUST TERROR" or "EQUITABLE TERROR".

In the second poster, the scene location is the view of the White House from across the South Lawn.

The English message reads as follows:

The branding in the upper left-hand corner is for the pro-ISIS media group Al Taqwa.

AlertsUSA again warns that many, but not all, attacks by the Islamic State in Western countries have been preceded by the release of propaganda posters and other public threats. Caution and vigilance are urged if you or your family intend to be in large public gatherings or venues during the end-of-year holidays.