- Militants cite Mali offensive as the reason for the kidnapping in nearby Algeria
- Americans, Japanese and Britons are among the hostages, officials say
- Militant group issues demands, says it has at least 40 hostages
- "The authorities do not negotiate, no negotiations," Algeria says
(CNN) -- The fallout from the French battle against militants in Mali reverberated globally after rebels kidnapped Westerners in neighboring Algeria, dragging governments beyond Africa into a daunting insurgency.
During the attack on a gas plant in the desert, kidnappers killed two people, including a British national.
Hostages included Algerians, Americans, Japanese and Britons, according to officials from those nations, who did not provide the number of people seized.
'Mr. Marlboro': The veteran jihadist behind the attack in Algeria
The rush of events sent governments scrambling to account for workers in the region as questions raged on the attacks.
Japan and the United Kingdom sent officials to Algeria to get the latest information.
While Ireland said there were reports that a citizen was involved, France declined to comment on whether its nationals were among the hostages.
The number of U.S. hostages could be as few as three, two U.S. officials said Wednesday.
Militants cited the offensive in Mali as the reason behind the kidnapping.
'No negotiations'
Before Algeria's state media reported late Wednesday that its nationals had been released, kidnappers had said they had at least 40 hostages.
The group holding the hostages has issued demands, according to the Algerian interior minister. The man behind the group claiming responsibility is a veteran jihadist known for seizing hostages.
Moktar Belmoktar, an Algerian who lost an eye while fighting in Afghanistan in his teens, has long been a target of French counter-terrorism forces.
"The authorities do not negotiate, no negotiations," interior minister Diho Weld Qabliyeh told state television. "We have received their demands, but we didn't respond to them."
Though he did not specify the demands, media in the region reported that the attackers issued a news release demanding an end to "brutal aggression on our people in Mali" and cited "blatant intervention of the French crusader forces in Mali."
In the news release, the militants said they carried out the operation in Algeria because it allowed French forces to use its air space in attacking Islamist militants in Mali.
They put the number of hostages at "more than 40," including seven Americans, two French, two British and other Europeans. Another Islamist group told the Mauritanian News Agency there were 41 "Westerners."
However, the Algerian Press Service reported that "a little more than 20 foreign nationals are held hostage."
'Terrorist attack'
U.S. Defense Secretary Leon Panetta, in Europe meeting with NATO allies, called the incident in Algeria "a terrorist attack."
As world powers scramble to limit the fallout, the United States is reviewing requests for support from the French in Mali, but no decisions have been made on specifics, said State Department spokeswoman Victoria Nuland.
Read more: Malian rebels vow to 'open gates of hell' as U.S. weighs policy options
Europe's largest powers appeared united in their goal of removing al Qaeda-linked militants from the West African nation, where Islamist rebels are fighting to form their own land in the north.
Other nations have pledged to contribute transport planes, including Germany, Belgium and Canada. Others such as Italy are pledging "logistical support" for the operation.
Read more: What's behind the instability in Mali?
War crimes investigation
French troops and warplanes have been helping Malian government forces stop Islamists from overrunning the capital, Bamako. French President Francois Hollande has said it was a "necessary decision" to go into the country, a former French colony.
"If we had not acted when we did, it probably would have fallen into the hands of terrorists," he said.
Hollande stressed that France was in Mali at the request of its government and within the framework of international law.
Mali was one of the most successful democracies in Africa until a coup toppled the president last year, leading the Islamists to capitalize on the chaos to establish themselves in the north.
In the quest to establish Sharia law, they have killed and mutilated residents who disobeyed them, leading the International Criminal Court to launch a war-crimes investigation.
Mali's government asked the U.N. tribunal to investigate in July, after Islamists seized much of the country, the court said.
CNN's Jethro Mullen and Tim Lister contributed to this report.
