Meeting in Vienna, the International Syria Support Group (ISSG), which comprises the United States, the Russian Federation, the UN, the Arab League, the European Union along with 16 countries, issued a statement, stressing the need to solidify the cessation of hostilities in the face of serious threats, particularly during the past several weeks.

The ISSG called on all parties to the truce to refrain from disproportionate responses to provocations and to demonstrate restraint. If the ceasefire is not implemented in good faith, “the consequences could include the return of full-scale war, which all the Members of the ISSG agreed would be in no one’s interest,” the statement said.

The ISSG also welcomed the joint statement of 9 May by Ceasefire Task Force Co-Chairs, Russia and US, in which they agreed to intensify efforts to ensure the cessation’s nationwide implementation.

The ISSG reaffirmed that sieges of civilian populations in Syria are a violation of international humanitarian law and called for the immediate lifting of all sieges, insisting on concrete steps to enable the delivery of urgent aid to the following locations: Arbeen, Darraya, Douma, East Harasta, Mouadhimiyeh, Zabadin and Zamalka.

The ISSG called on the World Food Program (WFP) to carry out a programme for air bridges and air drops for all areas in need, starting 1 June, if the UN is denied humanitarian access to any of the designated besieged areas.

The ISSG reiterated the objective of meeting the target date of August 1, set out by Security Council resolution 2254 (2015), for the parties to reach agreement on a framework for a genuine political transition, which would include a broad, inclusive, non-sectarian transitional governing body with full executive powers.

The ISSG reaffirmed that political transition in Syria must be Syrian-owned and Syrian-led, and expressed their unequivocal and united commitment to facilitating the start of political transition in Syria by consistent with resolution 2254 and previous ISSG statements of 30 October 30 and 14 November 2015, and 11 February 2016.

The ISSG also requested UN Special Envoy for Syria, Staffan de Mistura, to facilitate agreements between the Syrian parties for the release of detainees, calling on any party holding detainees to protect the health and safety of those in their custody.

 de Mistura told reporters in Vienna that he could not discuss the date for the next intra-Syrian talks, as it would depend on some factors, including the cessation of hostilities, humanitarian access, and the start of Ramadan.

“We need to bear in mind that credible intra-Syrian talks will become credible when […] there is a credible development on the cessation of hostilities and a credible improvement on the humanitarian side,” he said.

He warned that the ceasefire was holding at 80 per cent of the places, but it has come down to 50 per cent. “We need to bring it back [up] and there has been a strong effort and a common line on that,” he said.

Regarding the humanitarian aid, 12 of the 18 besieged locations have been reached, he said. If the UN cannot reach them by land, the WFP will conduct a joint operation with Russia, US and other countries to airlift aid to 110,000 people.

On the detainee s and abductees, the ISSG took note of that with serious concern because families are asking for their immediate release, he said.