The suicide bomber who killed seven CIA employees and wounded six others at an agency base in Afghanistan had been invited in and was not searched, former U.S. officials told The Associated Press Thursday.

Officials at U.S. Forward Operating Base Chapman, a CIA surveillance and intelligence post near Khost City in eastern Afghanistan, had been interested in using the man as an informant, according to the officials.

The region around the base is a hotbed of Taliban and insurgent activity because of its proximity to Pakistan's lawless tribal region. A senior CIA debriefer had apparently come from Kabul to meet with the man, the officials said.

The former officials familiar with Wednesday's attack spoke on condition of anonymity because they were not authorized to speak publicly.

The CIA would not confirm the details, and said it was still investigating.

"It's far too early to draw conclusions about something that happened just yesterday," said spokesperson George Little.

A separate U.S. official suggested the bomber may have detonated his explosive vest as he was about to be searched.

The Taliban claimed responsibility for the suicide attack in a statement Thursday.

Initial reports had indicated that eight American civilians had been killed.

CIA director Leon Panetta released a message Thursday saying that seven employees had died.

One of the victims was the base's chief, according to The Associated Press.

Former CIA officials said the Khost chief was a mother of three.

Also Thursday, a spokesperson for the governor of Helmand province in southern Afghanistan said an air strike by international forces killed and wounded civilians. The attack took place in Babajid district after an international forces patrol was attacked.

4 Canadian soldiers, journalist die

In a separate incident Wednesday, four Canadian soldiers and a journalist were killed after hitting a roadside bomb in the southern Kandahar province.

Brig.-Gen. Daniel Ménard, a top commander in Kandahar, said Thursday the men were dedicated to the military's mission to "bring stability to Kandahar City."

The soldiers killed were:

  • Sgt. George Miok, 28, of Edmonton.
  • Cpl. Zachery McCormack, 21, of Edmonton.
  • Sgt. Kirk Taylor, 28, of Yarmouth, N.S.
  • Pte. Garrett William Chidley, 21, of Langley, B.C.

Michelle Lang, a 34-year-old health reporter with the Calgary Herald, was the first Canadian journalist to die in Afghanistan, where she arrived just two weeks ago.

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.

It was the third-deadliest day for Canadians in Afghanistan since the war began.

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."

With files from The Associated Press