The ceasefire in Eastern Ghouta went into effect shortly after midnight (2200 UTC Friday) after Russia brokered a deal between rebels and Syrian regime forces.

A spokesman for the opposition Syrian National Coalition (SNC) in Vienna, Ahmad Ramadan, said, "A deal was reached Friday to implement a ceasefire in eastern Ghouta."

Rami Abdel Rahman, head of the UK-based Syrian Observatory for Human Rights said, "Rebels in the area have set the condition that humanitarian aid should enter the area in the coming 48 hours or else the agreement will be canceled."

Eastern Ghouta has been under siege for four years with 393,000 people cut off from receiving humanitarian aid.

Russia on Wednesday denied accusations that it and the Syrian army were behind a chemical attack in eastern Ghouta on January 22.

UN call for court action

United Nations Secretary-General Antonio Guterres again called for Syria to be referred to theInternational Criminal Court (ICC) for "serious violations" in blocking aid deliveries and medical care.

Guterres said that in December no aid was delivered to the more than 417,000 people in nine locations under siege. Only 60,000 of the 2.5 million Syrians in "hard to reach" areas had received humanitarian aid, the UN chief said in his report on the humanitarian situation in Syria delivered Friday to the Security Council.

The UN chief said "access for the United Nations and its partners to those people living in besieged and hard-to-reach locations remained a critical concern." He singled out eastern Ghouta, where prices for basic goods were 30 times higher than in neighboring Damascus city, "far beyond the purchasing power of most residents."

Guterres called on countries with influence over the Syrian government and opposition fighters to facilitate medical evacuations and humanitarian aid. Syrian authorities continued to reject or remove "life-saving and life-sustaining medical items" from convoys last month, he said.

But another call to refer Syria to the ICC is unlikely to succeed. Russia and China vetoed a Security Council resolution backed by 60 countries in May 2014 to refer the Syrian conflict to the international court.

Opposition boycott of Sochi talks

After two days of talks in Vienna with the UN special envoy for Syria, Staffan de Mistura, the Syrian opposition High Negotiations Committee (HNC) said it would not be attending peace talks being held in Russia next week.

"The HNC announces the boycott of the Sochi conference that Russia had invited it to," it stated on its Twitter account in Arabic on Friday.

Russia is reported to have sent out 1,600 invitations to its two-day "peace congress" in the Black Sea resort of Sochi next week to discuss a constitution for Syria.

Opposition spokesman at the UN talks in Vienna, Yahya al-Aridi said the Sochi talks were an attempt to undermine the UN efforts to broker a peace deal: "This whole round in Vienna was supposed to be a crucial one, a test for commitment. And we didn't see this commitment. And the UN didn't see this commitment."

De Mistura commented that Russia had said the Sochi talks were aimed at supporting the UN process: "I took note of the statement by the Russian Federation that the outcome of the (Sochi) congress would be brought to Geneva as a contribution to the intra-Syrian talks process under the auspices of the UN."

jm/sms (Reuters, AP)