The U.S. Defense Department says American Jessica Buchanan, one of two hostages rescued in Somalia by U.S. special operations troops, is being cared for at a military hospital. It would not say where.

Buchanan, and fellow aid worker Poul Hagen Thisted, a Dane, had been held for three months by gunmen in central Somalia. Wednesday night, several U.S. helicopters carried out a daring raid, and troops fought a gunbattle, killing at least nine kidnappers.

In announcing the rescue, President Barack Obama said the United States will “spare no effort to secure the safety of our citizens” and bring to justice those who take them seek to harm them.

On a Wednesday morning news program, Vice President Joseph Biden praised the troops who carried out the mission.

He says the timing of the operation was based in part on the health of the hostages.

“They said it was the time, the opportunity, Jessica's health was, was at a word, failing. They concluded they should go at this time. The president gave the go.”

Buchanan and Thisted worked for the Danish Demining Group, a unit of the Danish Refugee Council that helps clear landmines and other explosives in conflict zones in Africa and the Middle East. They were kidnapped in October in the central Somali city of Galkayo.

The raid took place just hours before President Obama gave his State of the Union address in Washington. Before speaking, President Obama could be heard by television microphones congratulating Defense Secretary Leon Panetta, apparently for the success of the rescue operation.

The Department of Defense is not identifying the unit that carried out the rescue. However, many news organizations, quoting unnamed U.S. government officials, say it was a Navy Seal team.

Officials say armed criminals, or pirates, appear to be responsible for the kidnapping. Somali pirates have increasingly carried out land-based kidnappings as foreign governments have boosted security on the high seas.

Several abductions for ransom have been carried out in Somalia and northern Kenya during the past several months. An American man was kidnapped near the Galkayo airport last week.