BBC News Online looks at how the siege of a school in the Russian town of Beslan, where more than 300 children and adults were taken hostage, developed.
All times approximate and local
Wednesday 1 September
0930 (0530GMT): Masked men and women, wearing bomb belts, burst into Beslan's School Number One, opening fire in the courtyard as a ceremony marking the beginning of the school year is finishing. Reports say they arrived from neighbouring Ingushetia in a hijacked Gaz-66 military lorry and police car.
Children and adults are then forced by the attackers into the school gym and the building is reportedly mined.
1125: Russian media report that at least 12 people have been killed, among them one of the hostage-takers.
1150: Reports say the attackers are threatening to blow up the school if troops try to storm the building. They are said to have sent the authorities a note with a woman hostage whom they released. In it they demand that two regional leaders and Dr Leonid Roshal - a negotiator during an earlier siege - be summoned for talks.
At the same time, the attackers are reported to be placing children on display at the windows of the building as human shields.
1220: A military spokesman tells Interfax news agency the school has been sealed off.
1230: Reports emerge that some children have managed to escape the school. They had apparently hidden when the attackers stormed the school and started leaving in small groups when shooting died down.
1240: The attackers demand the release of fighters seized in neighbouring Ingushetia in June during a raid on the region, Itar-Tass news agency reports.
1300: President Vladimir Putin breaks off his holiday and returns to Moscow for an emergency meeting on the siege.
1350: Mufti Ruslan Valgatov, religious leader of North Ossetia's Muslim minority, enters the school in an attempt to establish contact with the attackers, an official tells Itar-Tass. The group refuses to talk to him.
1400: The attackers reject a proposal to exchange schoolchildren held as hostages for two senior officials of North Ossetia, Russian radio reports.
1430: Reports say the attackers are threatening to kill 50 hostages for each killed member of the group.
1650: A government plane with a mobile hospital aboard lands at the nearby city of Vladikavkaz.
A presidential aide says that the hostage-takers are demanding the withdrawal of Russian troops from Chechnya as well as the other demands reported earlier.
1910: Russian media report that officials have established communication with the attackers who say none of the children have been hurt.
2400: One of the attackers tells the New York Times that they belong to a militant organisation called Riyadh al-Salihin, led by Chechen warlord Shamil Basayev.
Thursday 2 September
0130: Dr Roshal begins talks with the armed group.
0300: The attackers end contact with Dr Roshal - no agreement is reached.
1300: Russian authorities rule out the use of force to end the siege.
1500: President Putin says the main aim is to save the lives of the hostages, and adds that the security forces will make every effort to ensure that no lives are put at risk.
1530: Two loud explosions are heard and black smoke is seen over the school. It is thought the attackers fired at some vehicles outside.
1640: Following negotiations with former Ingush President Ruslan Aushev, the attackers release 26 women and children.
Friday 3 September
0230: BBC correspondent Sarah Rainsford at the scene says those freed indicated that the male hostages had been separated from the women and children.
0630: The night lull is broken by two rocket-propelled grenades fired from the school at Russian crack troops encircling the building. (AFP)
0830: Russian officials say they have resumed contact with the armed group.
The talks involving Dr Roshal are said to be focussing on efforts to persuade the hostage-takers to allow the delivery of food and water.
0930: Russian media reports, quoting released hostages, say the number of people being held may be more than 1,000 and perhaps even up to 1,500, far higher than the estimate of 330 advanced by authorities.
1130: According to North Ossetian President Alexander Dzasakhov, relaying demands given to negotiator Ruslan Aushev, the hostage-takers are separatists from neighbouring Chechnya and are calling for full Chechen independence from Russia.
Mr Dzasakhov adds that officials now believe that at least 500 people are being held hostage.
1300: Two loud explosions are heard, and heavy sustained gunfire ensues.
1320: Helicopters are overhead. Some children have been seen running from the buildings covered in blood. Eyewitnesses say part of the school has been blown up.
1330: A BBC correspondent at the scene says Russian troops are everywhere, with special forces taking up positions. Soldiers are taking some injured children and adults away on stretchers.
1340: An emergency military hospital has been set up in Beslan near the school to treat the injured, while ambulances are taking others away.
1555: Russian officials say they have the situation at the school under control but a "heavy gun battle" is still under way in the area, the BBC's Sarah Rainsford reports from the scene.
1 - Main entrance
2 - Area where gunfire began
3 - Hostages are being held in the school gym, which has reportedly been packed with explosives and mines
4 - Side entrance
5 - There have been reports of children being used as human shields at the back windows
6 - As the attack began a number of hostages hid in the boiler room and later escaped