At about 10:30 p.m. Tuesday, Stephen Buchanan heard the news his entire family had been hoping for the last three months: His oldest sister had been rescued in Somalia.

"I got a call from my dad, and he had been alerted by President Obama that the SEALs had gone in and rescued Jess and that she was OK, that she was safe and that she was in U.S. custody and we would be able to see her soon," said Buchanan, a student at Lee University in Cleveland, Tenn.

Jessica Buchanan, 32, and Danish citizen Poul Hagen Thisted, 60, were kidnapped on Oct. 25, 2011, in Galkayo, a city in central Somalia, a country on Africa's east coast. Both worked for the Danish Refugee Council. Jessica was an education adviser with the mine clearance unit, according to the nonprofit's website.

Stephen Buchanan said the family would be able to see his sister soon, but he couldn't disclose the location.

"We were all obviously so glad to know that they had rescued her and she was safe," said the 22-year-old. "They are the best news we could have gotten."

He said the last three months have been very stressful.

"It was very difficult, because you just don't know who it is who took her, why and what they want," he said.

The humanitarian aid workers were rescued by SEAL Team 6, the same group that killed Osama bin Laden last May in Pakistan.

One official said the SEALs parachuted from U.S. Air Force aircraft before moving on foot, apparently undetected, to the outdoor encampment where they found Jessica Buchanan and Thisted. The raid happened near the town of Adado.

Pentagon press secretary George Little said the captors were heavily armed and had "explosives nearby" when the rescuers arrived. He declined to say whether there was a firefight and would not provide details about the rescue except to say all the captors were killed by the Americans.

One defense official said it was likely that the SEALs killed the kidnappers rather than capture them because they encountered armed resistance or the threat of resistance.

The Pentagon cited a need to preserve the secrecy that can give SEALs and other special operations forces an edge against the terrorists, criminals and others they are ordered to kill or capture around the world under hazardous and often hostile conditions.

Special operations forces, trained for clandestine, small-team missions, have become a more prominent tool in the military's kit since the Sept. 11, 2001, attacks. The Obama administration is expected to announce today that it will invest even more heavily in that capability in coming years.

It was not clear whether any of the rescuers also participated in the bin Laden killing, the biggest counter-terror success of Obama's presidency.

The raid

The American raiders caught the kidnappers as they were sleeping after having chewed the narcotic leaf qat for much of the evening, a pirate who gave his name as Bile Hussein told The Associated Press by phone. Hussein said he was not present at the site but had spoken with other pirates who were, and that they told him nine pirates had been killed in the raid and three were "taken away."

A Pentagon spokesman, Navy Capt. John Kirby, said U.S. officials could not confirm that the kidnappers were engaged in piracy. He referred to them simply as "criminals."

Little said the decision to go ahead with the rescue was prompted in part by rising concern about Jessica Buchanan's health. Stephen Buchanan said he couldn't talk about it but did confirm her health was deteriorating.

Mary Ann Olsen, an official with the Danish Refugee Council, said Buchanan was "not that ill" but needed medicine.

Danish Foreign Minister Villy Soevndal told Denmark's TV2 channel, "One of the hostages has a disease that was very serious and that had to be solved." He did not provide any more details.

U.S. officials "within the last week or so" had collected enough information to "connect the dots" that led Obama to authorize the mission Monday, Little said.

A Western official said the rescuers and the freed hostages flew by helicopter to Camp Lemonnier in the nearby Horn of Africa nation of Djibouti. The official spoke on condition of anonymity because the information had not been released publicly.

U.S. Defense Secretary Leon Panetta visited Camp Lemonnier just over a month ago. A key U.S. ally in this region, Djibouti hosts the Combined Joint Task Force-Horn of Africa, a U.S.-led group organized under U.S. Africa Command.

Panetta and other members of Obama's national security team monitored the mission from the White House before traveling up Pennsylvania Avenue to the Capitol for the president's annual message to Congress and the nation.

Obama, Panetta and Ham all praised the skill and courage of the SEALs and expressed gratitude for the safe return of the hostages.

"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 said in a statement released by the White House on Wednesday.

"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."

The mission was directed by Army Gen. Carter Ham, head of Africa Command, from his headquarters in Stuttgart, Germany.

"We should remember that Mrs. Buchanan and Mr. Thisted were working to protect the people of Somalia when they were violently kidnapped," Ham said in a written statement. "It is my hope that all those who work in Somalia for the betterment of the Somali people can be free from the dangers of violent criminals."

The Danish Refugee Council had been trying to work with Somali elders to win the hostages' freedom but had found little success.

Stephen Buchanan said his sister had worked in Somalia for 21/2 years. He said the family knew she was heading to a particularly unstable place when she was kidnapped.

"It was definitely not something you are ever prepared for. It caught us very off guard," he said.

Jessica Buchanan worked as a teacher in neighboring Kenya before Somalia, her brother said, and has always been interested in humanitarian work. She graduated from Valley Forge University, a Christian college in Phoenixville, Pa., in 2007.

"She has always been interested in helping others," he said. "She's a hard worker, a great big sister."

The Buchanan family is grateful for the operation, he said.

"We are thankful for everyone who has been praying for her."

Several hostages are still being held in Somalia, including a British tourist, two Spanish doctors seized from neighboring Kenya and an American journalist kidnapped on Saturday.

The Associated Press and staff writer Perla Trevizo contributed to this report.