Panetta issued a statement on the hostage crisis unfolding in eastern Algeria from Kings College in London.
Algerian militants operating in support of al-Qaida in the Islamic Maghreb stormed a natural gas facility in the east of the country and are said to have several Westerners hostages. The facility is operated through a group led by BP, Norway's Statoil and state-energy company Sonatrach.
Panetta said the Defense Department was working closely with the British government in an effort to resolve the hostage situation.
"Terrorists should be on notice that they will find no sanctuary, no refuge -- not in Algeria, not in North Africa, not anywhere," he said in a statement. "Those who would wantonly attack our country and our people will have no place to hide."
Algerian militants are said to have stormed the facility in response to multilateral military operations in neighboring Mali. French boots are on the ground there and the U.S. and British militaries have pledged to provide logistical support for Malian operations.
British Foreign Secretary William Hague described the situation in Algeria as "fluid and evolving." Despite allegations that a unilateral operation launched by the Algerian military left some hostages dead, Hague said the responsibility for the events in Algeria "rests squarely with the terrorists."
"We are working around the clock to ensure the safe return of our citizens, and we will continue to be in close consultation with the Algerian government," added Panetta.