U.S. naval officials hosted Afghanistan President Hamid Karzai aboard an American carrier this week to assure him that the military is taking all precautions to avoid civilian casualties during airstrikes in his country.

U.S. Vice Adm. Bill Gortney, commander of the Navy's 5th Fleet, said naval officers walked Karzai through their process as they conduct air operations against suspected insurgents.

Gortney said that Karzai did not detail his concerns about civilian deaths in military strikes during the visit. But the Afghan president has made public his anger over recent strikes that left civilians dead.

The U.S. and its allies routinely turn to air power to combat Taliban and other insurgents because of Afghanistan's mountainous terrain and limited or impassable roads.

Karzai has said civilian deaths erode support for the war among his people and has pushed for a review of the use of U.S. and NATO air power.

Gortney said Karzai went aboard the USS Theodore Roosevelt for four to five hours, his first visit to a U.S. aircraft carrier.

He said they showed Karzai how they communicate with the aircraft and how decisions are made to execute the strike.

U.S. military officials, including Defense Secretary Robert Gates, have said they do all they can to avoid civilian deaths, including calling off airstrikes if innocent people are nearby. But Karzai has demanded investigations into recent incidents in which civilians died and demanded that U.S. and coalition forces exercise more caution.

According to Gortney, about one-third of the close air support for operations in Afghanistan comes from the sea. He said that about 28 combat runs are made daily from the Roosevelt into Afghanistan — and each one is six to seven hours long.

Asked about the expected increase in U.S. troop levels in Afghanistan — and whether they will require more ships in the region, Gortney said he has not requested any additional carriers to conduct air strikes.

He also said he has not — as yet — been asked by commanders to provide additional air combat missions. He said that he can increase the number of patrols a bit, but would need more ships for any substantial hike.

Karzai was invited to visit the Roosevelt a few months ago by Adm. Mike Mullen, chairman of he Joint Chiefs of Staff.

In recent months there have been several high-profile attacks in which civilians were killed. During a strike August 22 on the village of Azizabad scores of Afghan women and children were killed, according to Afghanistan officials.