Washington (CNN) -- The CIA created and controls a paramilitary force of 3,000 Afghans that conducts clandestine missions targeting al Qaeda and Taliban fighters in Pakistan, a U.S. official told CNN on Wednesday. The official described the force as "well-trained" and "effective." "You're talking about one of the finest Afghan fighting forces, which has made major contributions to security and stability," the official said. The official spoke on condition of anonymity because of the sensitive nature of the topic. The Counterterrorism Pursuit Teams were first revealed in a new book by Bob Woodward, associate editor at the Washington Post. "Obama's Wars," which lays out deep divisions in the Obama administration over Afghanistan strategy, will be released Monday.
@highlight
NEW: The teams stay in contact with "our allies in both Pakistan and Afghanistan," official says
@highlight
The paramilitary force is made up of 3,000 Afghans
@highlight
The Counterterrorism Pursuit Teams were first revealed Bob Woodward's new book
@highlight
Pakistan denies the presence of foreign forces
Pakistan
Pakistan
Pakistan
"We need to make clear to people that the cancer is in @placeholder," Obama is quoted as saying in Woodward's book, the Post said.
Pakistan
Pakistan
Pakistan
As the border area in Pakistan became more of a safe haven for al Qaeda, the Taliban and other extremists, the counterterrorism teams' mission expanded into @placeholder.
Pakistan
Pakistan
Pakistan
A former U.S. counterterrorism official said a team would enter @placeholder to gather intelligence and to provide targeting information to help the CIA take out suspected terrorists with missiles from unmanned aircraft.
Pakistan
Pakistan
Pakistan
This official said only a very few senior @placeholder leaders were aware of the teams and wondered what the fallout might be within Pakistan, suggesting the CIA's Afghan army could be "at tremendous risk" if it continues to operate in Pakistan.
Pakistan
Pakistan
Pakistan
But @placeholder officials refuted the claims that CIA-controlled forces are operating within Pakistan.
al Qaeda
The United States has "cut into their ability to plot, plan and train, but they remain very dangerous, and they are still the hub to all spokes, the heart of @placeholder," the U.S. official said.