15:26 - Explosion rocks Oslo
A massive blast shook the centre of Oslo at 15:26 (13:26 GMT) on Friday 22 July 2011, blowing out the windows of the prime minister's offices and damaging the finance and oil ministries. Eight people were killed.
Rubble and glass littered the streets and smoke from the fires drifted across the city from the devastated area - the heart of the Labour Party government. Witnesses described the scene as like a war zone.
Police set up cordons and evacuated buildings while ambulances took dozens of injured people to hospital.
Police confirmed the next day that the blast was caused by a car bomb, and that undetonated explosives remained in the area. The bomb contained an estimated 950kg (2,090lbs) of explosives made of fertiliser.
16:57 - Gunman arrives at lake
At about 16:57 a ferryman was asked to transport a policeman to the island of Utoeya, located in a lake about 35km (20 miles) north-west of Oslo, Norway's NTB news agency reported.
The uniformed man was said to have been armed with a pistol and an automatic rifle. He had described how he was there to "do research in connection with the bomb blasts", NRK journalist Ole Torp told the BBC.
But the policeman turned out to be a gunman, and he went on to shoot and kill scores of young people staying at the island camp. Although initial reports said about 10 people had been killed, the figure soared as horrific details emerged.
17:40 - SWAT team despatched
After the first reports of the shootings, at 17:26, a specialist police SWAT team was despatched from Oslo to Utoeya at 17:40.
Meanwhile, the gunman continued his killing spree undisturbed, randomly shooting victims, according to eyewitness reports.
Survivors described chaotic scenes as teenagers fled from the gunman, some plunging into the water to swim to safety. He shot at those who tried to swim away. Others hid in the undergrowth, cowering in fear.
Chilling descriptions have emerged of how the man - described as tall, blond and Nordic-looking - had called campers to him as if to offer help, only to open fire on them.
But the gunman did not take every chance to kill. A survivor, Adrian Pracon, told the BBC how he spared a 10-year-old boy who told him that his father was already gone and that he didn't want to die. Mr Pracon also survived after pleading for his life.
18:09 - SWAT team arrives at lake
Local police officers arrived at the pier across from the island at 17:52, but had to wait for a "suitable boat" to take them across the water.
The specially-equipped police officers from Oslo arrived shortly after at 18:09, but also had difficulty making the crossing.
Local police chief Erik Berga said a police boat intended to transport the armed unit nearly sank.
"When so many people and equipment were put into it, the boat started to take on water, so that the motor stopped," he told Reuters news agency. "The boat was way too small and way too poor."
Officers eventually arrived on the island at 18:25 after recreational boats were commandeered for the crossing.
Police have also defended their decision to drive to the lake, explaining that they believed it would have been quicker than scrambling a police helicopter, which was based in the south of the country.
18:27 - Gunman surrenders
Haarvard Gaasbakk, the leader of the first police squad to arrive on the island, said a group of youngsters directed them towards the gunman.
"We then spotted the gunman shooting on the southern part of the island and we hear a lot of shooting - the gunshots are coming fast and thick," he said.
As the officers ran into a clearing in the forest, they suddenly came face to face with the gunman, hands above his head and his weapons 15m away on the ground.
Mr Gaasbakk said the gunman was arrested and one officer took charge of him while the others ran to give the victims first aid.
The shooting spree had lasted more than an hour. Officers have said he still had "a considerable amount" of ammunition for both his guns - a pistol and an automatic rifle - when he surrendered.
Hospital sources said the gunman had used dum-dum bullets, designed to disintegrate inside the body and cause maximum internal damage.