"The situation is relatively more stable after the ceasefire that was agreed upon through Turkey and Russia… We encourage Turkey and Russia to continue to uphold the ceasefire and also to increase patrolling in the area. We believe this is a key," Pedersen said on Tuesday.
"This has led to increased civilian casualties and indeed also further displacement," he added.
Syria has been in a state of civil war since 2011, with the government forces fighting against numerous opposition groups and militant and terrorist organizations. Russia, along with Turkey and Iran, is a guarantor of the ceasefire regime in Syria. Moscow has also been providing humanitarian aid to residents of the crisis-torn country.