US Special Forces rescued an American and a Dane in Somalia on Wednesday after a shootout with the pirates who had taken them hostage.
The raid in the Horn of Africa nation freed aid workers, American Jessica Buchanan and Dane Poul Hagen Thisted.
The pair were kidnapped from the town of Galkayo in the semi-autonomous Galmudug region in October while working for the Danish De-mining Group (DDG).
"This is yet another message to the world that the United States of America will stand strongly against any threats to our people," US President Barack Obama said in a statement.
"Jessica Buchanan 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," Obama said.
"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," he added.
US military helicopters loaded with elite troops sweeoped to the pirate camp close to Haradheere, a major pirate base in central Somalia.
"All nine captors were killed during the assault," Washington's German-based African Command told reporters..
US Defense Secretary Leon Panetta confirmed no American soldiers were killed in the operation.
The Danish Refugee Council reported that Buchanan and Thisted had been extracted safely and taken to a secure location. Media reports said they had been flown to neighboring Djibouti, home to the only US military base in Africa.
Somali pirate gangs frequently seize ships in the Indian Ocean and Gulf of Aden and hold the crews until they receive a ransom. The kidnapping of the two aid workers was considered unusual.
US and French forces have intervened to rescue pirate hostages at sea, but attacks on pirate bases are very rare.
Danish Foreign Minister Villy Sovndal told reporters the rescue operation was launched due to reports that Buchanan was suffering from a kidney infection.
Sovndal said it did not necessarily set a precedent for future raids by Western forces.