Drawing the Line
Police stand next to a map of the Moscow metro transport system. 24 people died in the first blast at around 8.00am local time as a train stood at the central Lubyanka station, beneath the offices of the FSB (Federal Security Services) intelligence agency. Roughly 40 minutes later, a second explosion ripped through a train at Park Kultury, leaving another 13 dead. Officials suspect that the first attack was intended as a message to the security services, which have led the crackdown on Islamic extremism in Chechnya and other parts of the Caucasus region in southern Russia.

• Are Islamist Rebels Behind It?
• Behind Russia's Deadly Train Blast