DAMASCUS, Syria (AP) — A U.S. envoy said on Wednesday that Syria’s central government and the Kurds remain at odds over plans on merging forces after the latest round of talks.

U.S. Ambassador to Turkey Tom Barrack, who is also a special envoy to Syria, told The Associated Press after meetings in Damascus that differences between the two sides remain. Barrack spoke after meeying with Mazloum Abdi, head of the Kurdish-led Syrian Democratic Forces, and Syria’s interim President Ahmad al-Sharaa in the Syrian capital.

In early March, the new authorities in Damascus signed a landmark deal with the U.S.-backed, Kurdish-led Syrian Democratic Forces.

Under that deal, the SDF forces would be merged with the new national army. The agreement, which is supposed be implemented by the end of the year, would also bring all border crossings with Iraq and Turkey, airports and oil fields in the northeast under the central government’s control.

Detention centers housing thousands of suspected members of the Islamic State group would also come under government control.

However, the agreement left the details vague, and progress on implementation has been slow. A major sticking point has been whether the SDF would remain as a cohesive unit in the new army - which the Kurds have pushed for — or whether it would be dissolved and its members absorbed into the new military as individuals.

Barrack said that question remains “a big issue” between the two sides.