Citing military sources, Algerian state news said at least 685 Algerian workers and 107 foreign nationals were released during the three-day siege.
CNN said it was unable to confirm the figures reported by Algerian media and Algerian television said the death toll it reported Saturday was subject to revision.
ABC News reported the U.S. State Department had confirmed Fred Buttaccio of Texas was among the dead. The network said two other Americans, who it did not identify, were unaccounted for, while another American, Mark Cobb of Corpus Christi, Texas, was confirmed safe.
U.S. President Barack Obama issued a statement, saying "the thoughts and prayers of the American people are with the families of all those who were killed and injured in the terrorist attack in Algeria."
"The blame for this tragedy rests with the terrorists who carried it out, and the United States condemns their actions in the strongest possible terms," Obama said. "We have been in constant contact with Algerian officials and stand ready to provide whatever assistance they need in the aftermath of this attack. We also will continue to work closely with all of our partners to combat the scourge of terrorism in the region, which has claimed too many innocent lives.
"This attack is another reminder of the threat posed by al-Qaida and other violent extremist groups in North Africa. In the coming days, we will remain in close touch with the government of Algeria to gain a fuller understanding of what took place so that we can work together to prevent tragedies like this in the future."
Initial reports by Algeria's state news agency said seven hostages who were still being held were executed by their captors as commandos approached the facility Saturday, and 11 remaining hostage takers were killed in the raid by government forces.
The breakdown by nationality for the number of people killed, evacuated or missing was incomplete.
Norwegian Prime Minister Jens Stoltenberg said 13 Norwegians were involved and eight had been released but five were unaccounted for.
Five British nationals and one British resident were missing or feared dead, British Foreign Secretary William Hague said. One Briton was killed during the siege.
French officials had said one French national was killed but three others were safe.
Citing Algeria's state-run oil company Sonatrach, the Algerian Press Service said military forces had to clear mines planted by the militants.
Sonatrach said Saturday the raid was ordered because it appeared the hostage-takers were planning to escape with their hostages and then blow up the plant, The Washington Post said.
"It was found that the plant had been mined with the intention of exploding it," the statement said. "A major clearance operation is in progress by specialized teams of the Algerian army ahead of the launching of start up operations at the plant."
The hostage-takers, identified as Islamist militants, stormed the plant this week in apparent retaliation for France's intervention in neighboring Mali. The attackers claimed to be from a group called Signers in Blood and said they were convinced Algeria would assist the French in their Mali campaign, The New York Times reported.
CNN said notorious Algerian jihadist Moktar Belmoktar offered through a spokesman this week to facilitate the release of three American hostages in exchange for Sheik Omar Abdel Rahmam, the mastermind of the 1993 bombing of the World Trade Center.
Belmoktar is believed to have links to al-Qaida. His role in the gas plant takeover, if any, was not known.