The attackers had engaged in a running gunfight with the building's guards. The guesthouse is operated by Hart Security and serves as the firm's Afghan headquarters. The private British company provides security to businesses and diplomats.  An Afghan police official at the scene, Abdul Ghafar Sahab Zada, confirmed the four deaths -- those of the attackers and two drivers for Hart -- and said a security guard was wounded and taken to a hospital. Witnesses described seeing two young men, perhaps teenagers, running through the streets with their faces hidden, shooting at the building and the guards out front.  The building, several stories tall and fortified by a security wall topped with razor wire, was pockmarked with bullet holes. Glass was shattered on upper levels, and a car near the building was burned.  A bloody leg lay on the street. Officials lifted the torso and legs of a second body and wrapped them in a plastic sheet.  A Taliban spokesman said the insurgent group had carried out the attack, according to some news media reports, but that claim could not be independently verified.  The attack came as the U.N. Assistance Mission in Afghanistan released data showing that civilian casualties have risen 31 percent this year over 2009. The report showed that the spike has been caused largely by increased killings by the Taliban and other insurgent groups.  U.N. staff recorded 1,271 civilian deaths and 1,997 injuries. Of those casualties, insurgent forces were responsible for 2,477, while NATO and Afghan government forces accounted for 386.  "The job of the government is to fight the terrorists in Afghanistan, but if our actions cause the casualties of civilians, it is not justifiable in any way," Waheed Omer, a spokesman for President Hamid Karzai, said at a news conference Tuesday.  Omer reiterated Karzai's announcement last week that the government will seek the disbanding of all private security firms, which Omer said employ more than 30,000 well-armed, well-trained security officials. He called them "thieves by day, terrorists by night," saying they abuse their power and weaponry.  A call and two e-mail messages to the Hart office seeking comment went unanswered. The company's Web site said it was founded in 1999 by Lord Richard Westbury. "Hart's management team combines extensive experience in conventional and special forces military service and maritime expertise," according to the site.  The firm has offices in more than a dozen countries.  Special correspondents Javed Hamdard and Qadratullah Andar contributed to this report.
KABUL -- A new report that shows civilian casualties have soared in Afghanistan largely because of increased insurgent violence was thrown into relief Tuesday when a pair of suicide bombers blew themselves up and killed two other Afghans outside a foreign guesthouse in central Kabul.