The following is a list of the falsehoods that drew the most attention during the course of the tragedy:
Monday, August 14th:
The navy initially reported the disaster, saying it had taken place on Sunday. It took place on Saturday, as was revealed later by Norway.
The navy said the Kursk was crippled by "technical faults" and the crew allowed it to glide to the seabed. In fact, it was destroyed by explosions, quickly flooded and sank. Most of the crew were killed within minutes.
A Russian navy spokesman, Mr Igor Dygalo, said rescuers were in radio contact with the crew. In fact, there was no radio contact from the moment of the accident.
The navy said the crew had immediately signalled it had shut down the nuclear reactor. Officials later said the reactors' automatic system switched them off. In fact, since there was no radio contact, officials had no information from on board. There have been no radiation leaks.
Officials denied that the bow of the submarine was flooded, saying there was no damage to the hull.
Officials said they were lowering a diving bell to the submarine to supply it with electric power and oxygen for the crew. This did not take place.
Tuesday, August 15th:
A navy spokesman said the crew had signalled there had been no deaths on board. Officials said Russian rescue equipment and crews were in no way inferior to those being offered by the West. In fact, Russia has no teams of deep-sea divers capable of mounting an underwater rescue, and Russian rescue mini-submarines are not as advanced as those offered by the US and Britain.
Wednesday, August 16th:
The navy deputy chief of staff said the crew on board was continuing to signal by tapping on the hull. Later, officials said the last sound from the vessel came on Monday.
Friday, August 18th:
President Putin says accepting foreign help earlier would have made no difference because foul weather would have interfered with an international rescue. Western military experts said weather would have had little impact on a rescue operation underwater using their technology.
Mr Putin says he has known since the first day of the blast that the chance of anybody surviving on the ship was "extremely small", contradicting numerous optimistic reports.
Saturday, August 19th:
Russian officials acknowledged that damage to the vessel was massive, most of the crew died within minutes and the rest are almost certainly dead. It is not clear how long they had known this information.
Sunday, August 20th:
The Deputy Prime Minister, Mr Ilya Klebanov, said Norwegian divers had discovered the hatch to the submarine was too damaged to be opened. However, Norway said the divers made no such conclusion. They eventually opened the hatch with few problems.
Rachel Donnelly adds:
Downing Street said yesterday its head of policy was not involved in advising the Russian authorities on how to handle official information involving the sunken nuclear submarine Kursk.
On a visit to Russia before the presidential elections earlier this year, the Prime Minister, Mr Blair, offered Mr Putin the services of the head of No 10's policy unit, Mr David Milliband, and a Treasury official, Sir Nigel Wicks. It was envisaged that Russian officials would be given help in organising a policy unit along the lines used by Downing Street and organising an economic unit.
But a spokesman for Downing Street said he was sure the offer, which was long-term and open-ended, had not yet been taken up by Mr Putin or his officials and it would be "down to the Russians to arrange something", he said. "There is not any involvement in the submarine. Mr Milliband is not off to pick up the phone to help coach them on how to handle their media."
The spokesman also said if the offer was taken up, the British officials would travel to Russia where they would give advice on how to organise a central policy unit and how such a unit might brief ministers and officials on policy and economic issues.