"When it comes to terrorist attacks of this sort in North Africa, AQIM has to be at the top of the list of suspects, I'll put it that way," said Pentagon press secretary George Little, referring to al-Qaida in the Islamic Maghreb.
The White House said the Obama administration is working with the Algerian government to learn more about what happened and did not echo concerns expressed by the British defense minister over the Algerian government's collaboration.
"We cannot lose sight of the fact that the blame for this lies with the terrorists," said White House press secretary Jay Carney.
Little told reporters there are "strong indications that AQIM, "had a hand" in the assault on an Algerian natural gas plant that left dozens of hostages and militants dead, but he would not be more specific.
"AQIM does what terrorist groups do — they plan and carry out attacks. I'll leave it at that," he said.
The State Department has said three U.S. citizens were killed in last week's hostage standoff, while seven Americans made it out safely.
The State Department has not definitively declared that AQIM was responsible for the attack, but it has suggested the group played a leading role. Defense Secretary Leon Panetta has blamed the broader al-Qaida network.
Secretary of State Hillary Rodham Clinton last week described a "continuing effort by the terrorists, whether they call themselves one name or al-Qaida, to try to destroy the stability, the peace and security, of the people of this region."