United Nations Secretary-General Antonio Guterres has called for warring sides to implement a 30-day ceasefire across Syria, in line with an appeal by major powers at the weekend.
UN aid agencies are ready to deliver life-saving aid and evacuate critically wounded from the rebel-held Damascus enclave of eastern Ghouta, where 400,000 people have been living under siege, Guterres said.
"Eastern Ghouta cannot wait, it is high time to stop this hell on earth," Guterres told the UN Human Rights Council, which opened its main four-week annual session in Geneva.
The remarks were Guterres' first to a UN 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."
UN human rights chief Zeid Ra'ad al-Hussein said air strikes on eastern Ghouta were continuing on Monday morning.
Zeid decried "seven years of failure to stop the violence, seven years of unremitting and frightful mass killing" in Syria.
