Afghan President Hamid Karzai (search) on Saturday met with the chief of the U.S. Central Command (search) and told him that the country's three main problems remain terrorists, drug trafficking and provincial warlords.

Gen. John Abizaid (search), whose command territory includes Afghanistan and Iraq, met for about 45 minutes with Karzai at the Presidential Palace in the capital, Kabul, to discuss the military situation in the country, deputy presidential spokesman Hamed Elmi told The Associated Press.

The closed meeting also was attended by Zalmay Khalilzad (search), an Afghan-American who formally took up his position as the new U.S. Ambassador to Afghanistan on Saturday. Khalilzad, an ethnic Pashtun, previously served as President Bush's special envoy.

Later, in a speech on state-run television, Khalilzad said he was determined to help Afghanistan rebuild itself and join forces with neighboring countries such as Pakistan in the global war against terrorism. He spoke in the Afghan language of Dari.

Gen. Abizaid "briefed President Karzai about the security situation in Afghanistan, saying it has improved, but that U.S. forces continue to follow terrorists and attack them," Elmi said.

Two years after the hardline Taliban (search) regime was driven out of Kabul, the capital, 11,600 U.S.-led coalition forces are fighting terrorist cells in Afghanistan. An additional 5,700 international peacekeepers patrol Kabul.

Some 35 Americans have died from hostile fire in Afghanistan since the October 2001 start of the Afghan war, according to the U.S. military.

On Friday night, three Afghan men in a car opened fire when they were stopped at an Afghan checkpoint near a U.S. base in the eastern city of Khost. In the shooting that followed, one of the attackers was killed and two arrested, state-run TV and a local official said.

Abizaid's visit comes as U.N. and relief agency workers are being targeted by increased pro-Taliban and pro-Al Qaeda (search) terrorist attacks, especially in the south and east.

On Thursday, Sen. Hillary Rodham Clinton (search) said during a visit to Afghanistan that more troops are needed in the multinational military coalition providing security.

Four months into the NATO-led operation in Kabul, the alliance is still lacking specialist troops, helicopters and other equipment for its force in the capital.

The need to fill the shortfalls is expected to be a major theme at a meeting of alliance defense ministers Monday and Tuesday in Brussels.

The spokesman said Karzai told the general that Afghanistan's three major problems remain terrorist attacks, a booming drug trade and powerful warlords who control many of the provinces.

The United Nations recently reported that poppy cultivation has skyrocketed in Afghanistan since the fall of the Taliban, making it the source of about three-quarters of the world's opium. Opium is used to make heroin and morphine, and can be a much more profitable crop for the country's poor farmers than wheat.

Security is of particular concern in Afghanistan now, ahead of next month's loya jirga, or grand council, in Kabul to ratify a new constitution.