"The northeast would be represented. There are already some people from the northeast in the third - 50 people - chosen by the UN. They’re less represented than other areas", Jeffrey said on the sidelines of the UN General Assembly in New York.
Jeffrey also said that he cannot confirm that the names in the list of the Syrian Constitutional Committee members, which has been published, are accurate.
"I know who the 150 names are in fact I think people have already published that ... people have been publicizing names, I just cannot confirm that those are the true names," Jeffrey said on Thursday.
According to the list obtained by Sputnik, the Syrian government and opposition, and civil society are represented equally within the body, which will be tasked with reviewing the Syrian constitution.
Notably, there would be at least 30 women in the 150-strong body, the list showed.
On Monday, UN Secretary-General Antonio Guterres announced the formation of the Syrian Constitutional Committee and said that the body would be convened in the coming weeks. Syrian Foreign Minister Walid Muallem said on Tuesday that the inaugural meeting of the committee in Geneva had been tentatively set for 30 October.
However, the self-proclaimed Kurdish-led autonomy in the northeast of Syria had rejected the committee, claiming it failed to include its representatives.
The conflict in Syria between President Bashar Assad's government and various opposition groups and terrorist organizations has been ongoing since 2011.
In May 2017, the warring parties held talks in the Kazakh capital under the mediation of Russia, Iran and Turkey, and managed to conclude a ceasefire agreement. The parties also met in January 2018 in the Russian city of Sochi, where the landmark agreement to form the constitutional committee was reached.