CAMP DAVID, Maryland - In a show of unity, U.S. and Afghan officials laid the groundwork for new relations between the two countries on Monday, including plans to seek American funding to maintain an Afghan security force of 352,000 and long-term counterterrorism efforts. Discussions over future U.S. troop levels continue as the war winds down.

In an all-day session at the Camp David presidential retreat in Maryland's Catoctin mountains, dozens of U.S. and Afghan officials, including Secretary of State John Kerry, Defense Secretary Ash Carter, Afghan President Ashraf Ghani, and chief executive Abdullah Abdullah, gathered to relaunch a relationship strained by nearly 14 years of war and often-testy relations with former Afghan President Hamid Karzai.

During the meeting, the United States agreed to seek funding through 2017 for an Afghan force of 352,000, a level the nation has yet to meet, Carter said. U.S. officials said the Afghan government is trying to improve recruiting to make up for security forces who leave the service.

They also agreed to require the Afghan government to complete specific reforms and meet other milestones in order to receive up to $800 million. U.S. officials said the Afghans suggested the incentive-based funding idea. The leaders of the two nations also said they would restart routine ministerial-level Defense and State Department meetings.

Ghani is to meet with President Obama on Tuesday, an engagement during which officials expect the U.S. to make clear its decision to slow the pace of the withdrawal of American troops from Afghanistan. Ghani and Abdullah fought a contentious election last year to replace Karzai, and their power-sharing agreement was lauded by Kerry, who played a key role in brokering it.

"It is easy today to underestimate the measure of courage and leadership and selflessness that was demanded at that moment, and that both of these leaders continue to show in their commitment to a unity government," Kerry said.

He added that "huge challenges remain" but that the agreements to be reached this week will help pave the way for stability and security.

Kerry said that the joint appearance at Camp David, along with the White House meetings, should serve as notice to the Taliban that the U.S.-Afghan relationship is back on track and they should negotiate rather than fight.