SAUDI ARABIA: The first attacks were timed to ambush foreign oil and construction experts as they returned to work after the Muslim weekend. It was 7.15 a.m. on Saturday. The traffic was building up on the palm tree-lined highways in Khobar.
Wearing uniforms and using cars with military markings, several car-loads of armed Islamists drove up to two commercial complexes. Their disguises were designed not to arouse the suspicion of the Saudi security guards.
Within minutes, bursts of gunfire rang out across the streets of the Saudi Gulf port, triggering a security alert as news of the attacks spread among the city's panicking commuters.
"I was on my way into the office," said Angel, a Filipino administrative worker who would give only his first name, "but there were vehicles stopped in the street, so I couldn't turn in to the building. I thought it was a traffic jam or an accident.
"There were people gathered around a petrol station, watching. I pulled in where I could see the building. Then I heard firing. The gunmen were still inside. I got out of my car and ran away. I ran as fast as I could and I hid behind the bucket of a bulldozer. There was more shooting going on. After about 20 minutes, some heavily armoured cars and the police arrived."
He added: "Then the shooting came out on to the street. Everyone who was sheltering scattered."
The two sites targeted were the five-storey Al Rushaid Petroleum Centre and the vast, modernist headquarters of the Arab Petroleum Investment Corporation (Apicorp).
The Petroleum Centre - which has two linked buildings - houses scores of Western firms involved in the oil industry. Witnesses at the scene yesterday said Resource Sciences Arabia Ltd (RSAL) was one of those where staff were killed.
The second ambush came at the front gate of Apicorp. The undulating roof and courtyards of the complex were designed to create cool comfort in the searing, summer heat of the Gulf city. But there was little protection for Michael Hamilton, the 62-year-old British oil executive who arrived for work shortly after 7.15 a.m.
The militants opened fire at the security gate, killing two guards waiting for his car to drive in. Saudi television yesterday showed pictures of a black, bullet-ridden vehicle believed to have been that of Mr Hamilton. A mobile telephone, smeared with blood, lay on the front seat.
The attackers then opened fire on a bus carrying schoolchildren, killing a 10-year-old Egyptian boy, the son of another Apicorp employee.
Mr Hamilton had just dropped his wife off on the way to work, a spokesman for Apicorp, Mr Marhdi Al-Marhdi, told BBC television yesterday.
"The gunmen were targeting those arriving at the gate. They shot Mr Hamilton in his car. They killed two of the security guards and then they shot at the school van carrying children, and killed one of them."
Then, in an act calculated to terrify and humiliate the expatriate community which staffs much of Saudi Arabia's oil industry, the gunmen tied the body of one of their foreign victims - thought to be that of Mr Hamilton - to a car and dragged it through the streets. It was eventually dumped beside a bridge.
The militants fled and regrouped at the luxury Oasis Residential Resorts compound, a maze of private villas, hotels and leisure centres inhabited mainly by privileged foreign workers and secured behind high walls.
The compound even contains an ice-skating rink and grassy poolside beach. Employees of Royal Dutch/Shell, Total and the Russian company Lukoil are among its residents.
In a series of raids on villas and private homes, the gunmen began rounding up foreign hostages. According to Arab survivors, the Islamists tried to separate out the non-Muslims. (After past attacks on housing compounds, al-Qaeda was heavily criticised in the Arab press for having killed Muslims from other Middle Eastern states.)
Five Lebanese hostages were reported to have been questioned, but eventually released. One of them, Ms Orora Naoufal, told reporters she had cowered in her apartment with her four-year-old son for five hours after an encounter with two of the gunmen, whom she described as clean-shaven and wearing military uniforms.
The men had asked her where the "infidels" and foreigners were, and whether she was Muslim or Christian. "I replied: 'I am Lebanese and there are no foreigners here.'" The gunmen, she said, instructed her to "go convert to Islam and cover up and go back to your country".
According to another survivor, Mr Abu Hashem, an Iraqi with a US passport, there were four gunmen, aged between 18 and 25, wearing military fatigues. "Don't be afraid. We won't kill Muslims, even if you are an American," he said they told him. They had been polite and calm, he said.
"They gave me a lecture on Islam and said they were defending their country and ridding it of infidels. [They were] so polite. I cannot comprehend this politeness they showed me because I am a Muslim, and this cruelty to others."
Having grabbed as many foreign hostages as they could find, the militants then retreated to the top floor of the six-storey Tower Hotel within the compound. Saudi security forces who moved in to surround the building found the lower floors booby-trapped with explosive devices and had to abandon an initial rescue operation.
Saudi newspapers reported yesterday that the attackers had thrown at least one body from the top floor of the hotel and had mutilated some of the bodies of those they had killed.
Attempts at negotiation failed. The Saudi ambassador to the US, Prince Bandar bin Sultan, said yesterday that the authorities had to take action after the gunmen began doing "evil things" to the hostages. A gun was reportedly held to a child's head.
Shortly after sunrise yesterday morning, three Saudi security force helicopters flew in fast over the compound and dropped off commandos. Bursts of gunfire could be heard, but the fighting was over quickly. Several of the gunmen were said to have been killed, and at least two - one described as a ring-leader - were taken into custody.
The official death toll had risen to 22 by early evening. As the siege ended a bus carrying Saudi troops and other police and military vehicles left the compound. A Saudi soldier flashed a V-for-victory sign from the window.
Meanwhile, six ambulances lined up to enter the compound.