Monday, March 29 was just the start of another working week in Moscow. Huge crowds of people descended into the metro system – a rumbling, winding maze of tunnels, walkways and escalators.

Within a single hour, two suicide bombers struck at the heart of the Russian capital. Blasts shook key stations on the busy red line, which dissects the centre of the city – first at Lubyanka, home of the FSB (formerly KGB), and then Park Kultury, a ten-minute ride to the south.

Park Kultury station, March 29

By mid-afternoon, everything at Park Kultury appeared to be calm. Police were out in force, but many were smoking or chatting idly on their mobile phones. Ambulances were gathered around the vestibule connecting the red line to street level (above), but the station’s main entrance across the road was open. A small group of photographers, TV cameras and general bystanders clustered behind the barriers.

Within hours the system was back up and running, but anxiety afflicted commuters. Moscow’s central ring road, the Sadovoe Koltso (Garden Ring), was suffering traffic levels even more brutal than usual; the photo below was taken on March 30. Rush-hour congestion is serious even in normal circumstances, but an infectious sense of paranoia had exacerbated the situation. The emergency services were on high alert – police and ambulance sirens seemed to be squealing past my bedroom window every five minutes.

Garden Ring road, March 30

March 30 was declared a day of national mourning. The next evening, down on the platform, a mass of flowers, candles and condolences had been building up (below). A constantly shifting flow of people stood in silence, gazing blankly at the temporary shrine almost in disbelief.

Park Kultury station, March 31

While terrorism and militant attacks are nothing new to the country, more than six years had passed since the last such act in Moscow. A typically Russian sense of steely resolve and determination to soldier on was tempered by grief and residual shock – pretty much every person would pause to stand and stare before continuing their journeys.

Park Kultury station, March 31

Similar scenes awaited at Lubyanka station (below), which was first to be hit on Monday morning. Many believe it was targeted for symbolic significance – the infamous Soviet-era KGB had its headquarters here – and the area lies within walking distance of the Kremlin itself.

Lubyanka station, March 31

The same evening, a remembrance gathering was held on Lubyanka square. Thousands of people attended the wake, but a couple of hours later the place was virtually deserted. Forsaken. Three policemen watched over a sea of candles.

Lubyanka square, March 31

The bombers took 40 lives, wrecking many more, and dozens remain in hospital. Chechen resistance leader Doku Umarov has claimed responsibility, promising this will not be the last attack on the Russian heartland in a video statement posted on YouTube.

The Guardian reports that the Moscow strikes came in response to civilian killings in a February counter-insurgency operation.

On March 31, suicide blasts caused 12 more deaths in Dagestan – a republic neighbouring Chechnya in the troubled North Caucasus. In these regions, far from the westernised, developed side of Russia, such incidents are part of everyday life.

As the Caucasus conflict now looks certain to intensify, we can only hope Moscow will not be a main battleground.