After nearly 16 years of war against the Taliban, the Afghan government is starting to develop a "road map" for breaking a battlefield stalemate that has been prolonged by the insurgents' ability to use Pakistan as a sanctuary, the Pentagon said Tuesday.

In a report to Congress, the Pentagon said Kabul's plan is in the early stages of development. It would restructure and realign the Afghan force to "set conditions for offensive operations," including "large-scale offensive operations in 2019," the report said.

The new approach has four key elements: increase the Afghan military's fighting capabilities; improve its development of leaders; generate a more unified command effort; and counter official corruption. It also would double the size of the Afghan "special security" forces, without changing the size of the overall security structure, the report said.

"With renewed interest in planning for the future, Afghanistan has demonstrated its intent to face a myriad of challenges, furthering its commitment to be a viable security partner to the United States," the report said.

The report makes no mention of a new U.S. strategy for the Afghanistan war, which Defense Secretary Jim Mattis says should be ready for public release in July. Earlier this month the administration said President Donald Trump had given Mattis the authority to set U.S. troop levels in Afghanistan. Mattis is expected to announce, in connection with the new U.S. strategy, that he is adding nearly 4,000 more U.S. troops, although his office said he had not yet made a decision.

The U.S. now has about 8,400 troops in Afghanistan, down from a peak of 100,000 in 2010-11.

Tuesday's Pentagon report, which provides a detailed assessment of conditions in Afghanistan and is required by Congress every six months, said Pakistan continues to provide sanctuary for elements of the Taliban insurgency, including the Haqqani network.

"Attacks in Afghanistan attributed to Pakistan-based militant networks continue to erode the Afghanistan-Pakistan relationship," the report said. "Militant groups, including the Taliban and Haqqani network, continued to utilize sanctuaries inside Pakistan."