A woman walks to lay flowers at a makeshift memorial near the Crocus City Hall following last Friday's deadly attack on the concert venue in Moscow. Reuters
At least 139 people were killed and more than 180 hospitalised after a group of gunmen attacked the concert hall in Moscow. Reuters
The Russian rock band Picnic was due to perform at the Crocus City Hall before the attack. EPA
On Tuesday, police officers were on high alert as they guarded the Oktyabrsky Concert Hall, ahead of the 'Picnic' rock concert in St. Petersburg. EPA
Police officers checked people heading to the concert hall. EPA
Military cadets walk in front of the Oktyabrsky Concert Hall on March 27. EPA
Police officers keep watch outside the Oktyabrsky Concert Hall, amid heightened security measures in the wake of a terrorist attack at the Crocus City Hall concert venue, prior to the concert of the rock group 'Picnic' in St. Petersburg, Russia. EPA
Riot police check the bags of spectators as they guard an area at the Oktyabrsky Concert Hall prior to the concert of the rock group 'Picnic' and the symphony orchestra 'Tavrichesky' in St. Petersburg, Russia, Wednesday, on March 27. AP
Cadets of the Fire and Rescue College stand in front of at a makeshift memorial near the Crocus City Hall following a deadly attack on the concert venue in the Moscow Region, Russia, on March 27. Reuters
Russia on high alert post Moscow attack - in pictures
Police were on guard at all major venues and they conducted thorough security checks