The assailants made their way through streets patrolled by 350 soldiers, past the gate of a secure residential area and the security guards standing in front of the foreigners' homes.
The boldness of last week's raid underscores the reach of a terror group that was formed just four years ago, and whose growing footprint has now turned entire regions of Africa into no-go zones for foreigners.
"It shows a new level of brazenness," said Adam Raisman, a senior analyst for SITE Intelligence Group, which monitors terrorist activity. "Here they are carrying this out in an area that is indoors and well-guarded, rather than in a remote area where there is less risk of getting caught."
At least a dozen foreigners including Spanish, Swiss, British and Canadian nationals have been kidnapped by al-Qaida in Islamic Maghreb, or AQIM, over the past several years.
But in each of those cases, the victims were snatched outdoors while they were driving in remote locations. A group of four European tourists was returning from a Tuareg cultural festival in northeastern Mali when the attackers shot out the tires of their 4-by-4. A convoy of Spanish aid workers came under attack on a stretch of road in Mauritania where they had gone to deliver supplies.
Last Thursday's attack in the town of Arlit where French nuclear giant Areva runs a 2,500-person uranium mining operation marks the first time foreigners were seized indoors and in a secure area. Five French citizens were abducted along with one person from Togo and another employee from Madagascar.
Fleur Floquet, a spokeswoman for Areva, said the mining town is patrolled by 350 of Niger's soldiers as well as by 150 private security guards employed by Areva.
The attackers entered the town at around 2 a.m. and made their way past the gate to the VIP residential area where the foreign employees of the nuclear company live, she said. Both the gate and each of the houses where the employees lived is guarded by security personnel, she said.
The French government has been flying reconnaissance planes over the vast desert and a contingent of 80 French soldiers were dispatched to Niamey, Niger's capital. French Defense Minister Herve Morin says authorities believe the hostages were likely taken to northern Mali, the terror group's main operating base.
On Thursday, Morin said the French government is willing to speak to al-Qaida's North African wing in order to find a solution to the crisis.
Al-Qaida in the Islamic Maghreb, or North Africa, grew out of an Islamist insurgency movement in Algeria that merged with al-Qaida in 2006. In just four years, the militants expanded their violence beyond attacks on Algerian authorities to make entire swaths of northwestern Africa have become off-bounds to tourists.
The U.S. Embassy now warns against travel to northern Mauritania, northern Niger and northern Mali, including such Lonely Planet staples as Timbuktu. The French and the British embassies have issued similar warnings to their citizens.
The group already has made millions of dollars by kidnapping Westerners for ransom.
"There's a higher degree of cognizance by these criminals that you can kidnap white people and sell them down the line to the highest bidder. A chain of incentives has been created," said Mike McGovern, an expert on Africa and an assistant professor of anthropology at Yale University.
Not all abductions by al-Qaida's North Africa branch have ended in ransoms though. British hostage Edwin Dyer was beheaded by the group in 2009.
And in July, the group said it had executed a 78-year-old French aid worker it had taken hostage three months before, saying the killing was in retaliation for the deaths of six al-Qaida members in a French-backed military operation against the group.
If France refuses to pay a ransom this time, then the kidnappers have limited options, McGovern said. If they don't kill the hostage, it looks like they won't follow through.
"In a sense they have to show their seriousness of purpose," he said. "Everybody's playing with fire in a situation like this."