"The most important thing now, the thing I discuss with the Normandy Quartet representatives is deciding on the makeup of the working subgroups within the Trilateral Contact Group on Ukraine," Dacic said.
The OSCE chairperson added that the four subgroups will deal with security, political and economic issues and humanitarian activities respectively.
Dacic also said that OSCE monitors have observed breaches of the ceasefire agreement in eastern Ukraine after the Minsk II peace deal, brokered by the Normandy Group of Russia, France, Germany and Ukraine, was signed in February.
The OSCE and the Trilateral Contact Group are tasked with overseeing the implementation of the Minsk II accords, which also include the pullout of heavy artillery from the line of contact.
The OSCE Special Monitoring Mission was first deployed to Ukraine in March 2014 and was extended until March 2016 last month.
More than 6,000 people have been killed after an armed conflict erupted between Kiev and the self-proclaimed Luhansk and Donetsk People's Republics in April 2014, according to UN estimates.