Pedersen succeeds Staffan de Misutra, who steps down this month after four years of peace efforts that led nowhere.

Deputy Foreign Minister Faisal Mekdad told the pro-government daily Al-Watan that Syria would cooperate with Pederson if he commits to the country's territorial integrity and stops supporting "terrorists, as his predecessor did."

The government regularly refers to the opposition as "terrorists."

The conflict, now in its eighth year, has killed more than 400,000 people, displaced half of the country's population and left entire neighborhoods and towns in ruins. It has also drawn in international powers, with Russia and Iran backing the Syrian government and a U.S-led coalition and Turkey also sending in troops.

Beginning in July 2014, de Mistura convened several rounds of indirect peace talks between the government and the opposition, with little success. Russia started a separate process that resulted in local cease-fires but failed to kick-start a political process.

De Mistura's latest efforts focused on negotiating a joint government-opposition committee to draft a new Syrian constitution. The government largely rejected those efforts, saying they amounted to meddling in its internal affairs.

Pedersen previously served as U.N. special coordinator for Lebanon in 2007 and 2008, and was a member of Norway's team that negotiated the 1993 Oslo accords between Israel and the Palestinians.