Secretary-General Ban Ki-moon said a full, immediate cessation of hostilities is needed in Syria and must be accompanied by discussions of what will follow. Fighting could escalate without such negotiations, he warned.
"I call on all regional and international actors to use their influence on the parties, and to persuade them to negotiate in good faith on transitional arrangements," Ban said during an evening address at the annual Doha Forum in the Qatari capital. "Is there anything more urgent than resolving that nightmare?"
More than 20 countries involved also agreed to boost humanitarian aid, aiming to get help to areas cut off by fighting by a June 1 deadline, though UN-mediated talks between representatives for Syrian President Bashar Assad and opposition groups have yet to resume.
The UN envoy for Syria, Staffan de Mistura, has said he wants to see signs of progress following the meeting before setting a date for a resumption of the talks.
Ban also cautioned against using "short-sighted policies and heavy-handed approaches" to confront violent extremists in the region, saying they only exacerbate problems and serve as recruiting tools for terrorists.