WASHINGTON -- As two aid workers freed by a Navy SEAL team flew out of Somalia to be reunited with family, details emerged Wednesday about the rescue operation that the Pentagon says left nine captors dead.

Vice President Joe Biden told NBC's "TODAY" show that the U.S. decided to stage the rescue because of concerns that the health of American Jessica Buchanan "was beginning to decline."

"We wanted to act," Biden said.

Buchanan, 32, and Dane Poul Thisted, 60, were kidnapped on Oct. 25, and then held for ransom. They both work for the nonprofit Danish Demining Group and had just finished training Somalis on how to clear mines when they were captured.

A Pentagon spokesperson in Washington characterized the captors as "criminal suspects," adding that the U.S. military has no firm indication they were connected to piracy or to any terror group, NBC News reported.

The first official recognition of the rescue operation came Tuesday night in Washington from President Barack Obama himself. 

Danish Refugee Council

Poul Hagen Thisted

As the president entered the House chambers to give his State of the Union Speech, he pointed to Defense Secretary Leon Panetta standing in the crowd and said, "Leon. Good job tonight. Good job tonight."

The president made no mention of the hostage rescue, but finished his speech with a reference to the killing of Osama bin Laden last May in a similar operation to the one conducted by Navy SEALs Tuesday night. 

Immediately after the speech, Obama telephoned Buchanan's father from the Capitol to tell him that she was safe and "on her way home," according to the White House.

According to the U.S. officials, two teams of Navy SEALs landed by helicopter near the compound where the two hostages were being held. 

STORY: Second American, a writer, held in Somalia; rescue next?

As the SEALs approached the compound on foot gunfire broke out, the U.S. officials said.

Pentagon officials said the Americans originally intended to capture alive and detain the kidnappers. Instead, for reasons that have not been explained publicly, they killed all nine of them.

Tuesday's rescue was carried out by the same SEAL unit that killed Osama bin Laden, two U.S. officials said, speaking on condition of anonymity to discuss the operation. The unit is the Naval Special Warfare Development Group, also known as SEAL Team 6. The members of the unit who carried out the rescue operation were not the same personnel as those who killed bin Laden, the officials said.

STORY: Overnight Navy SEAL rescue frees hostages

Panetta's press secretary, George Little, said the kidnappers were heavily armed, with explosives "nearby." He said neither the two hostages nor any members of the U.S. assault team were injured.

An official for the group the finances the Danish Demining Group said Buchanan and Thisted were flown to Djibouti and would soon be moved to a "safe haven."

The Danish Refugee Council official, Mary Ann Olsen, added that Buchanan, who reportedly was running low on some medication, did not need to be hospitalized.

"One of the first things Poul and Jessica were able to do was to call their families and say they were freed," Olsen said. "They will be reunited with their families as quickly as possible," Olsen said.

Buchanan lived in neighboring Kenya before Somalia, and worked at a school in Nairobi called the Rosslyn Academy from 2007-09, said Rob Beyer, the dean of students.

She graduated in 2006 from Valley Forge Christian College, a small suburban Philadelphia school.

This article includes reporting by NBC Pentagon correspondent Jim Miklaszewski and The Associated Press.

More from msnbc.com and NBC News:

• 3 years after US accident, boat washes up in Spain
• American hostage in Somalia rescued by Navy SEALs
• Report: Amanda Knox 'loves Italy' and might return
• Envoy: US dead dishonored by Afghan split 'lies'

Updated at 7:15 p.m. ET: Navy SEAL Team 6, the unit that killed Osama bin Laden, also rescued an American and a Dane held hostage in Somalia, U.S. officials said, but the same service members were not involved in both missions, U.S. officials said. Wednesday.

Updated at 12:30 p.m. ET: The Navy SEALs that rescued the American and Danish hostages in Somalia on Tuesday were not the same individuals who killed Osama bin Laden, U.S. officials told NBC News, contradicting an earlier news service report.

Published at 1:15 a.m. ET: In a daring nighttime raid Tuesday, U.S. Navy SEALs rescued two hostages, including one American, who were being held by kidnappers in Somalia, U.S. officials tell NBC News.

American Jessica Buchanan, 32, and a 60-year-old Dane, Poul Thisted, were working for a Danish relief organization in northern Somalia when they were kidnapped last October. U.S. officials described their kidnappers as heavily armed common criminals with no known ties to any organized militant group.

According to the U.S. officials, two teams of Navy SEALs landed by helicopter near the compound where the two hostages were being held. 

As the SEALS approached the compound on foot gunfire broke out, the U.S. officials said, and several of the militants were reportedly killed. There is no word that any of the Americans were wounded.

Danish Refugee Council

Poul Hagen Thisted, a Danish national who was taken hostage in Somalia alongside American Jessica Buchanan in October 2011. The pair were freed by a U.S. Navy SEALS raid.

The SEALs gathered up Buchanan and Thisted, loaded them onto the helicopters and flew them to safety at an undisclosed location. The two hostages were not injured during the rescue operation and are reported to be in relatively good condition.

The two had been working for the Danish Refugee Council on a demining project in northern Somalia. The humanitarian group has been providing relief to some 450,000 refugees in the Somalia-Kenya border region.

News reports at the time said the two were kidnapped Oct. 25 along with a Somali colleague when their three-car convoy was stopped on the way to an airport. A self-proclaimed Somali pirate said they had been kidnapped for ransom by pirates stymied by Western nations' efforts to stop the seizure of ships off the coast. The fate of the Somali colleague was unclear.    

STORY: Second American, a writer, held in Somalia; rescue next?

The first indication of the rescue operation came Tuesday night in Washington from President Barack Obama himself. 

As the president entered the House chambers to give his State of the Union Speech, he pointed to Defense Secretary Leon Panetta standing in the crowd and said, "Leon. Good job tonight. Good job tonight."

The president made no mention of the hostage rescue, but finished his speech with a reference to the killing of Osama bin Laden last May in a similar operation to the one conducted by Navy SEALs Tuesday night. 

Updated at 5:57 a.m. ET: In a statement sent to NBC News and other media, Obama says that he authorized the operation to rescue Buchanan.

"Thanks to the extraordinary courage and capabilities of our Special Operations Forces, yesterday Jessica Buchanan was rescued and she is on her way home," he says. "As Commander-in-Chief, I could not be prouder of the troops who carried out this mission, and the dedicated professionals who supported their efforts."

Obama, who spoke to Buchanan's father Tuesday night, says she was "selflessly serving her fellow human beings when she was taken hostage by criminals and pirates who showed no regard for her health and well-being."

He says he told her father that "all Americans have Jessica in our thoughts and prayers, and give thanks that she will soon be reunited with her family."

"The United States will not tolerate the abduction of our people, and will spare no effort to secure the safety of our citizens and to bring their captors to justice," Obama adds. "This is yet another message to the world that the United States of America will stand strongly against any threats to our people."

Updated at 6:50 a.m. ET: A statement from U.S. Africa Command says U.S. forces had received "actionable intelligence" about Buchanan and Thisted and decided to take action.

"During the course of the operation, the rescue force patrolled to the location and confirmed the presence of Mrs. Buchanan and Mr. Thisted guarded by nine captors," the statement says. "All nine captors were killed during the assault."

General Carter F. Ham, of U.S. Africa Command, says in the statement that the raid, which took place near Gadaado, was "boldly conducted by some of our nation's most courageous, competent, and committed special operations forces."

"Thanks to them a fellow American and her Danish co-worker are safe and will soon be home with their families," he adds.

Updated at 6:55 a.m. ET: A statement from Panetta says he is "grateful to report that there was no loss of life or injuries to our personnel."

He says the rescue -- "undertaken in a hostile environment" -- showed the "superb skills of courageous service members who risked their lives to save others." 

"They are heroes and continue to inspire all of us by their bravery and service to our nation," he says.

Updated at 10:35 a.m. ET: Pentagon officials told NBC News that they are characterizing the people who took Buchanan and Thisted hostage as "criminal suspects,"  rather than pirates. They said the U.S. military has no firm information about whether the captors were connected to pirates or an Islamic militant group like al-Shabaab.

See more of Jim Miklaszewski's reporting on the SEALs raid tonight on NBC's Nightly News with Brian Williams.

 More from msnbc.com and NBC News:

• Envoy: US dead dishonored by Afghan split 'lies'
• Danger zone then and now: Strait of Hormuz
• Interpol faces legal threat for helping regimes hunt dissidents