Transcript for Americans Targeted in Afghanistan
civilians since the start of the war. Those three Americans killed, two of them working for American university there. The third worker working for the united nations. The Taliban is taking responsibility for the attacks, a rare act to go after civilians. Afghan security forces rushing to the scene when the attack began after dark and in the light of day what was left, the building there in shambles. We ask how did those attackers get through so many check points in what was typically a very secure neighborhood for Americans working there. Here's ABC's hamish McDonald. Reporter: The after math of one of kabuls most stunning attacks but this is no ordinary target, the wealthiest, the safest area. 21 people were killed, mostly foreigners including three American civilians. We strongly condemn these attacks. It's unacceptable and they must come to an immediate halt. Reporter: Somehow the attackers made their way inside what should be a secure zone. It's dinner time, just after 7:00 P.M., a suicide bomber blows himself up at the restaurant gate and then a fire fight lasting almost two hours. In the end, the attackers, too, are dead. Some of the staff injured themselves. The question is, how could it happen here? Security check points mark all of the main routes into this area. Part of a so called ring of steel around central kabul. There are 25 road blocks in total manned by almost 1,000 police officers every day. Tributes are flowing in tonight for the three U.S. Citizens killed. One worked for the U.N. The other two for the American university. The Taliban describes it as a revenge attack for the deaths of Afghan civilians. This week the Taliban claimed it would regain control of the entire country as soon as foreign forces leave. Tonight the state department says the U.S. Remains steadfast in its commitment to Afghanistan. In truth, most American, british and allied soldiers will be gone by the end of this year and the Afghans will be left to fend for themselves. Thank you and welcome to ABC. We turn next here on the broadcast to our other major
This transcript has been automatically generated and may not be 100% accurate.