Tonight, we begin with the american hostages taken captive by terrorists wit links to al qaeda. It has been a day of chaos, details still pouring in about a deadly rescue operation, helicopters... See More
Tonight, we begin with the american hostages taken captive by terrorists wit links to al qaeda. It has been a day of chaos, details still pouring in about a deadly rescue operation, helicopters circling overhead and a frightening scene below. It happened in the north african nation of algeria and abc's chief global affairs correspondent martha raddatz spent the day with the defense secretary, leon panetta, in italy, as he was tracking every new development. Martha? Reporter: Diane, this is a very fluid situation but reports we are getting tonight about the raid are very ominous. A u.S. Official telling me tonight there were ten americans at the field, five are safe. But the fate of the other five, we do not know. What is clear tonight is that this is far from over. With algerian forces now surrounding the complex, the british prime minister is warning that this raid could end in even more bloodshed. It is a very dangerous, very uncertain, a very fluid situation and I think we have to prepare ourselves for the possibility of bad news ahead. Reporter: The worst, coming after the algerian military moved in with helicopters, reportedly fearing the hostage takers were going to escape. The terror group was holed up in the natural gas plant along with their hostages, the americans and other workers from britain, france, japan and norway. Some reportedly forced to wear explosives around their necks. Tonight, algeria is saying the raid left not only some of the militants dead, but some of the hostages, as well. But it is not clear how many. And the battle is ongoing. A u.S. Official saying tonight it is believed that between 15 and 20 hostages still remain inside. The militants say this is in retaliation for the french-led assault against isl islamic rebels in the nearby country of mali. Today, the secretary of defense, monitoring developments here in italy, spoke to us exclusively. I don't think there's any question that based on what we do know that this was a terrorist act and that the terrorists have affiliation with al qaeda. Reporter: But secretary panetta told us that the rest of the information coming from algeria is murky. We're going to look at what the situation is, how best to address it, how can we bring our military assets to bear in order to deal with it. Reporter: We do know that one IRISH CITIZEN, stephen McFall, escaped the complex. He talked to his family afterwards. Just really excited. Can't wait until he comes home. Reporter: An official items us tonight, a u.S. Surveillance drone has moved over that field to try to get more clarity. What other military as sets may be used, they are keeping that secret, for good reason. They don't want to put those remaining hostages in harm's way including those five americans.
This transcript has been automatically generated and may not be 100% accurate.