Country hit by several terrorist attacks in 2017

Russian President Vladimir Putin on Thursday called an explosion that tore through a Saint Petersburg supermarket, wounding 13 people, "an act of terror."

Russian authorities regularly claim they have foiled terror plots, often releasing videos of security services busting presumed members of the Islamic State group or the Russian militant jihadist organisation the Caucasus Emirate.

Here is a reminder of the principal attacks Russia suffered in 2017:

- On April 3, a bomb in the Saint Petersburg metro killed 15 people and wounded dozens. The attacker, a 22 year-old national of Kyrgyzstan in Central Asia, also died in the blast. The "Imam Shamil Battalion", a little known al-Qaeda linked group, claimed responsibility.

The deadly blast was the first in Russia since October 31, 2015, when a bomb exploded on a plane carrying Russian holidaymakers from Egypt, killing all 224 people on board. IS claimed the attack, which came a month after Moscow launched air raids in Syria to shore up Bashar Al-Assad's regime.

- On April 6, IS claimed responsibility for the killings of two traffic policemen in the southern Russian city of Astrakhan as well as an attack that wounded three National Guard soldiers in the same city.

- On August 19, a knife attacker wounded seven people on the street in Surgut, a city in Western Siberia, before being shot by police. IS claimed responsibility, although authorities ruled out terrorism.

- On August 28, two men stabbed one policeman to death and wounded another in Russia's North Caucasus Dagestan republic before being shot dead by police in an attack claimed by IS.

Despite the IS claim, Russian investigators treated the killings as criminal and not terrorist acts.

IS said on October 3 that it was behind an an attack which, according to the group, left two policemen dead in Dagestan.