WASHINGTON: U.S. Defense Secretary Leon Panetta told visiting Afghan President Hamid Karzai Thursday that the two countries had reached the “last chapter” in their effort to establish a sovereign Afghanistan that can provide for its own security.

After a formal welcoming ceremony at the Pentagon, Panetta told Karzai that 2013 would mark an important turning point in the war, with Afghan forces due to begin taking the lead role in providing security across the country while coalition troops offered support and training.

“We’ve come a long way toward a shared goal of establishing a nation that you and we can be proud of, one that never again becomes a safe haven for terrorism,” Panetta said in remarks at the start of meetings in his office. “Our partnership, forged ... through almost 11 years of shared sacrifice, is a key to our ability to achieve the final mission.”

Karzai’s three-day visit to Washington follows a year of rising strains on the U.S.-Afghan partnership, including a spate of incidents in which Afghan military or police attacked and killed U.S. or coalition troops. U.S. forces were involved in a series of incidents that enraged Afghans, including burning Qurans, which set off days of rioting.

Karzai’s visit comes as the two countries are in the midst of discussions on an agreement that would govern the role of any U.S. forces in Afghanistan after most combat troops withdraw at the end of 2014.

The Obama administration has been considering maintaining a residual force of between 3,000 and 9,000 troops in Afghanistan to conduct counterterror operations while providing some training and assistance for Afghan troops.

But the administration said earlier this week it did not rule out the possibility of a complete withdrawal of all U.S. troops after 2014.

While Karzai has been critical of U.S. troop activity in Afghanistan, it is unclear how Afghan troops would perform without U.S. helicopters, medical facilities, intelligence and other military support activity, of which Afghanistan has very little.

Karzai, in remarks in Panetta’s office, said he was confident that during his trip Afghanistan and the United States would be able to “work out a modality for a bilateral security agreement to ensure the interests of Afghanistan and also the interests of the United States.”

The United States is insisting on immunity for any U.S. troops that remain in Afghanistan. That unsettled question is expected to figure in this week’s talks and may come up at the White House Friday, when Karzai meets President Barack Obama.

Panetta thanked Karzai for visiting U.S. and Afghan wounded at the Walter Reed National Military Medical Center outside Washington, and he noted that the visit followed 11 years of war, blood, battle and sacrifice on both sides.

“After a long and difficult past, we finally are, I believe, at the last chapter of establishing ... a sovereign Afghanistan that can govern and secure itself for the future,” Panetta said, adding that continued cooperation would be key to completing the mission.

Karzai expressed appreciation for years of support and training of Afghan troops by the United States and coalition partners.

“I assure you Mr. Secretary that Afghanistan will be able to provide security for its people and to protect its forces. So Afghanistan will not ever be threatened by terrorists from across our border,” Karzai said.