Afghanistan war strategy is working, Gates says (UPDATES) (VIDEO)

U.S. Defense Secretary Robert Gates said Tuesday that he saw reason to believe that the Afghanistan war strategy was working.

"I do feel like the pieces are coming together," he told reporters at Combat Outpot Kowall west of Kandahar, The Associated Press reported.

Gates said Monday he would use his 13th visit to Afghanistan to gauge progress in the war at a time of rising tensions with Afghan leaders over civilian casualties.

President Hamid Karzai last week expressed frustration over reports international forces killed several Afghan children in military operations. Gen. David Petraeus, the top U.S. military commander in Afghanistan, apologized personally to the Afghan president for the accident.

Karzai said the apology his apology for the deaths of nine boys out collecting firewood was "not enough."

President Barack Obama agreed with the Afghan president that such incidents undermined the joint effort to fight terrorism, according to UPI.

Gates on Monday also apologized for the incident. “This breaks our heart,” he said at a press conference, Bloomberg reported.

U.S. and international forces will hand over some responsibility to Afghan forces in July. Karzai last year said he would like his forces to assume responsibility over all military operations in the country by 2014.

Gates said Tuesday he was encouraged by signs of stronger connections between the efforts of international military forces, Afghan national police, the Afghan army and local police forces backed by village and tribal elders.

Pentagon spokesman Geoff Morrell in a statement quoted by UPI said of Gates' visit: "Frequent, regular visits provide [Gates] with good measuring sticks to determine how rapidly progress is being made."