As he justified sending 30,000 more troops to Afghanistan at a cost of $30 billion a year, President Barack Obama's description Tuesday of the al-Qaeda "cancer" in that country left out one key fact: U.S. intelligence officials have concluded there are only about 100 al-Qaeda fighters in the entire country.

A senior U.S. intelligence official told ABCNews.com the approximate estimate of 100 al-Qaeda members left in Afghanistan reflects the conclusion of American intelligence agencies and the Defense Department. The relatively small number was part of the intelligence passed on to the White House as President Obama conducted his deliberations.

President Obama made only a vague reference to the size of the al-Qaeda presence in his speech at West Point, when he said, "al-Qaeda has not reemerged in Afghanistan in the same number as before 9/11, but they retain their safe havens along the border."

A spokesperson at the White House's National Security Council, Chris Hensman, said he could not comment on intelligence matters.

Obama's National Security Adviser, Gen. James Jones, put the number at "fewer than a hundred" in an Oct. interview with CNN.

Sen. Jeanne Shaheen (D-NH) referred to the number at a Senate Foreign Relations Committee in Oct., saying "intelligence says about a hundred al-Qaeda in Afghanistan."