Day one: Saturday 12 August

• Russia's Northern Fleet Command loses contact with the Kursk nuclear submarine taking part in exercises in the Barents Sea.

Day two: Sunday 13

• A Russian sonic depth finder from the Pyotr Veliky cruiser finds the submarine, which has sunk to the sea bed at a depth of 108 metres, approximately 135km (85 miles) off Severomorsk

Day three: Monday 14

• A Russian navy official admits that the Kursk is on the seabed. It is claimed radio contact was made with submarine. This is later denied - the only way that survivors can communicate with their rescuers is by knocking on the hull

• Officials say there are no nuclear weapons on the Kursk and say that the submarine's nuclear reactor has shut down. The Russian navy says the accident happened on Sunday

• Russian officials play down reports that the Kursk collided with a foreign vessel, and suggest that an explosion took place on board

• The UK and the US are among nations that offer to help Russian rescue efforts

• There are unofficial reports that the knocking on the Kursk has stopped

Day four: Tuesday 15

• First unofficial reports emerge from Washington that US submarines monitored two explosions in the area where the Kursk sank

• Raging storm hampers rescue efforts. The Russian navy attempts to lower a submersible vessel to the Kursk. Strong currents and the angle at which the sub is lying on the seabed mean that the submersible fails to latch onto the Kursk

Day five: Wednesday 16

• Poor underwater visibility hampers rescue efforts. New attempts to dock with the Kursk fail

• President Vladimir Putin, who is on holiday in southern Russia, makes his first public comment on the crisis. He describes the situation as critical and says Russia has everything it needs to conduct the rescue mission

• Shortly afterwards, Deputy Prime Minister Ilya Klebanov says that there are no signs of life on the submarine

• Late on Wednesday, Russia formally asks the UK and Norway for help

• A plane carrying British navy LR5 mini-submarine leaves Scotland for Trondheim, Norway

Day six: Thursday 17

• Further Russian attempts to dock with the Kursk fail

• The supply ship carrying the British LR5 and crew sails from Trondheim. The Seaway Eagle, carrying Norwegian divers, heads for the scene of the accident

• Russian officials report extensive damage to the Kursk, saying the entire bow has been ripped open. It is reported that many of the crew were likely to have been in the sections of the submarine destroyed by the impact and are believed to have died instantly

Day seven: Friday 18

• A Norwegian seismological institute says it registered two powerful explosions on Saturday in the area of the accident at approximately 0730 GMT

• A Russian rescue capsule briefly latches on to the submarine. Damage to the hatch prevents a secure docking, Russian officials say

• President Putin returns to Moscow to monitor the crisis

Day eight: Saturday 19

• The British rescue team and the LR5, arrives at the scene of the disaster but is not deployed

• The Norwegian ship, the Seaway Eagle, carrying Norwegian divers arrives at scene.

Day nine: Sunday 20

• A remote-controlled camera goes down to Kursk from Seaway Eagle to inspect the body of the submarine

• The first Norwegian diver reaches the sub

• Norwegian divers say the rear submarine hatch is not too damaged to attempt opening it

Day ten: Monday 21 August

• Norwegian divers open outer hatch. The airlock below is found to be flooded with water, but no bodies are discovered

• A few hours later, they open the airlock's inner hatch. The cabin inside is flooded and rescuers conclude the crew is dead

• The Russian navy officially announces that all 118 crew are dead