The Taliban claimed responsibility Thursday for bombings that killed 14 people, including eight Americans and an Afghan in a suicide attack in the volatile east, and five Canadians in the south. CIA employees were believed to be among the victims. It was unclear how the bomber at US Forward Operating Base Chapman at the edge of Khost city was able to circumvent security. Khost is the capital of Khost province, which borders Pakistan and is a Taliban stronghold. Taliban spokesman Zabiullah Mujahid said in a statement that an Afghan National Army officer wearing a suicide vest entered the base and blew himself up inside the gym. A US official who was briefed on Wednesday's blast also said it took place in the gym. The explosion killed eight American civilians and one Afghan, the worst loss of life for the US in the country since October. Six Americans were wounded, the official said. Harold E. Brown Jr., a State Department employee of Fairfax, Va., died in the attack, his father, Harold E. Brown Sr., told The Associated Press on Thursday. The younger Brown, 37, who grew up in Bolton, Mass., served in the Army and remained a major in the reserves. He is survived by a wife and three children ages 12, 10 and 2. Separately, four Canadian soldiers and a journalist embedded in their unit were killed the same day by a roadside bomb in the southern Kandahar province, the bloodiest single incident suffered by the Canadian military in 2009. Michelle Lang, a 34-year-old health reporter with the Calgary Herald, was the first Canadian journalist to die in Afghanistan. She arrived in the country just two weeks ago. There was no independent confirmation that the bomber in the attack on the US base was a member of the Afghan military. Gen. Mohammad Zahir Azimi, spokesman for the Afghan Ministry of Defense, said no Afghan National Army soldiers are at the base. But an Afghan official in Khost said the US has hired about 200 Afghans to help with security at the base. They are usually deployed on the outer ring of its walls, although some work inside, the official said on condition of anonymity because of the sensitivity of the issue. "It's not the first time that Afghan forces have conducted such an attack to kill Americans or foreigners," the Taliban statement said, citing the alleged killing of an American soldier and the wounding of two Italians this week in Badghis province. NATO has provided no details of that incident, but Afghan Gen. Jalander Shah Bahnam said an Afghan soldier opened fire on a base in the province's Bala Murghab district. A US congressional official said CIA employees were believed to be among the victims of Wednesday's attack. The CIA has not yet commented on or confirmed the deaths. A former senior CIA officer who was stationed at the base said a combination of agency officers and contractors operated out of the remote outpost with the military and other agencies. All the US officials spoke on condition of anonymity because they were not authorized to discuss the matter with the media. NATO said only that the base is used by provincial reconstruction teams, which consist of both soldiers and civilians, and other personnel. A spokesman in Kabul for the international coalition force said no US or NATO troops were killed in the explosion. The attack was the deadliest for Americans since eight soldiers were killed in an insurgent attack on a base in eastern Afghanistan on Oct. 3. Only four known CIA operatives have been killed in Afghanistan since the Sept. 11, 2001 terrorist attacks. CIA officer Micheal "Mike" Spann was killed in a prison uprising in November 2001. An agency officer died in a training exercise in 2003, and two contractors operating out of a CIA base in Shkin district of Paktika province were killed the same year. In Wednesday's other attack on Westerners, NATO said the four Canadian troops and the reporter died when their armored vehicle hit a bomb while on an afternoon patrol south of Kandahar city. It was the third-deadliest day for Canadians in Afghanistan since the war began. Lang "was one of those journalists who always wanted to get to the bottom of every story so this was an important trip for her," said a Calgary Herald colleague, Colette Derworiz. The military has not disclosed the names of the Canadian troops because relatives have not all been notified. Brig. Gen. Daniel Menard, commander of coalition forces in Kandahar, said the soldiers were conducting a community security patrol. According to figures compiled by The Associated Press, 32 Canadian troops have been killed in Afghanistan this year; in all, 138 have died in the war. Afghan President Hamid Karzai issued a statement of condolence to Americans and Canadians, saying "your children sacrificed their lives for the people of Afghanistan and the threat of terrorism. The Afghans will not forget your sacrifice." Also Thursday, a spokesman for the governor of Helmand province in the south said an airstrike by international forces killed and wounded civilians. Dawud Ahmadi said he did not know how many were killed Wednesday in Babajid district. He said the attack took place after an international forces patrol came under fire. NATO said it was aware of the reports and was investigating. Claims of civilians killed by foreign forces are a highly emotional issue among Afghans and feed strong resentment of international soldiers. Separately, police said terrorists beheaded six Afghans for cooperating with government authorities. Juma Gul Hamit, police chief of Uruzgan province in south-central Afghanistan, said the men were killed near the provincial capital of Tarin Kot. He said a seventh victim was being treated for serious neck wounds.