Benomar denied a report that delegates from southern Yemen, long oppressed by Saleh's regime, had walked out of talks. He said some had left but they had not quit en masse, and some who were continuing to participate in the dialogue would hold a news conference on Thursday.
Outside U.N. headquarters, a group of southern Yemeni protesters demanded the region's secession from Yemen.
Hadi took over from Saleh in February 2012 after a year of protests demanding Saleh's ouster. Hadi's inauguration ended 34 years of one-man rule under Saleh, a polarizing figure who divided his opponents for decades before the protests shook his hold on power.
Hadi, who was Saleh's vice president, has been supported by the international community and regional powers to transition Yemen to a more democratic rule. He faces the challenge of restructuring a security sector studded with Saleh loyalists and family members.