Panetta called the event a “terrorist attack” in remarks to reporters in Italy, according to the Associated Press.
“I want to assure the American people that the United States will take all necessary and proper steps that are required to deal with this situation,” he said according to news reports.
An Al-Qaeda-linked group, Al-Qaeda in the Islamic Maghreb (AQIM), has claimed responsibility for the attack, claiming the action came in retaliation for Algeria’s support of French military intervention in Mali aimed at subduing militants there.
Two people are reported killed with an unknown number of others injured. As many as 41 people – including Japanese, Norwegian, British and Irish personnel – are believed to be in captivity after militants began a raid around 05:00 GMT on Wednesday, according to reports.
Reuters reported US Secretary of State Hillary Clinton had called Algerian Prime Minister Abdelmalek Sellal and US ambassador in Algeria on the situation.
“Beyond confirming that there are Americans among the hostages, I will ask you to respect our decision not to get into any further details as we try to secure these people,” State Department spokeswoman Victoria Nuland reportedly told a news briefing.
AQIM, which operates in the Sahara desert and Europe, said it carried out the attack, according to Mauritania’s ANI news agency.
The Algerian interior ministry said: “A terrorist group, heavily armed and using three vehicles, launched an attack this Wednesday at 5 am against a Sonatrach base in Tigantourine, near In Amenas, about 100 km from the Algerian and Libyan border.”