Participants in two demonstrations demanded the release of Naama Issachar.
The protests were held simultaneously at Tel Aviv's Habima Square and the Russian Consulate in New York.
At 10:00, when the lights in Issachar's prison cell are turned out, the lights at Habima Square will also be turned off.
The protesters called for Issachar's freedom, holding signs claiming that "the process was unfair - now's the time to fix it," and "where are you when we need you?" Other signs called simply for "justice for Naama" and to "free Naama."
Issachar was sentenced to 7.5 years in a Russian prison for possessing 9.5 grams of marijuana while passing through a Moscow airport. Though she claims to have "no idea" how the drug got into her bag, just prior to her arrest, she told a friend that she was "in much bigger trouble than we hoped."