U.N. Secretary-General Antonio Guterres says it's "high time to stop this hell on Earth" in Syria's embattled eastern Ghouta region.

Guterres also appealed on the warring sides to abide by a 30-day cease-fire called for by the U.N. Security Council. He spoke at the start of a session Monday of the U.N.-backed Human Rights Council.

The remarks were Guterres' first to a U.N. body since the 15-member council unanimously adopted a resolution demanding a 30-day truce across Syria over the weekend.

Guterres says he welcomes the resolution but added that council resolutions "are only meaningful if they are effectively implemented."

He says he expects the "resolution to be immediately implemented and sustained." Guterres also called for safe, unimpeded and sustained delivery of humanitarian aid and services, and evacuations of the sick and wounded.