Moscow ? Drivers in downtown Moscow squinted in disbelief as an electronic highway billboard blazed a two-minute pornographic video instead of its regular advertising clips.

Late-night traffic on one of the Russian capital’s busiest roads slowed Thursday as a couple’s explicit escapades appeared on the 9-by-6-yard display.

Some people took pictures of the sight with their mobile phones and posted them on the Internet.

Passer-by Alyona Prokulatova told The Associated Press that she was “so shocked that I couldn’t even shoot video or take a picture of it.”

The screen’s owner, 3 Stars, told the AP that a hacker attack was likely to blame.