At least 10 people are reported dead after an explosion on a trolley in Volgograd, Russia, Reuters reported.
On Sunday a suicide bomber attacked a train station in the same city, killing at least 17 people, Reuters noted.
Volgograd is 400 miles northeast of Sochi, where the Winter Olympics are scheduled to take place next February.
Suicide bombings and other attacks linked to Islamic rebels roaming the North Caucasus have rocked Russia for years, the Associated Press said.
The government has deployed tens of thousands of soldiers, police and other security personnel to protect the Olympics, President Vladimir Putin’s pet project, the AP noted, and the organizers have pledged to make the Sochi Games the “safest Olympics in history.”
This is breaking news; updates will be added.