World power talks on ending the Syrian conflict broke up with no clear breakthrough today as new faction-fighting erupted and the death toll continued to mount.
US Secretary of State John Kerry and his Russian counterpart Sergei Lavrov said the Syria contact group they co-chair had agreed to bolster a shaky ceasefire.
But underlying disagreements between Washington and Moscow on how to handle the crisis were on plain display, and the United Nations failed to name a date for new peace talks.
Meanwhile, human rights monitors said fierce new clashes between the rebel Jaish al-Islam and Al-Qaeda-backed factions had left 50 fighters and two civilians dead.
And United Nations envoy Staffan de Mistura said he could not invite Bashar al-Assad's regime and the Syrian opposition back to peace talks until there was a "credible" ceasefire.
Kerry said the International Syria Support Group (ISSG) had agreed there would be consequences for parties breaching the truce and vowed to maintain pressure on Assad.
But Lavrov restated the Russian position that Assad's army is the best placed local faction to fight the Islamic State "terrorist" group and that Moscow would support it.
The evident divisions between Russia and the United States have cast a pall on efforts to agree a framework under which Syria would "transition" away from Assad's rule.
And Kerry admitted the August 1 date set by the UN Security Council for agreement on the political framework was a "target" not a deadline, apparently softening the US stance.
Nevertheless, Kerry said the ISSG had agreed to strengthen its system for monitoring the ceasefire and that violators risked being expelled from the process.
Washington regularly accuses Assad's forces of violating the truce and of bombing civilians, whereas Russia accuses rebel factions of carrying out massacres.
"We have agreed consequences for any side's actions that have an agenda other than that of trying to reach an agreement and trying to reach peace."
The top US diplomat again accused Assad's forces of deliberately starving besieged areas and said UN humanitarian agencies would be ordered to drop food.
From June 1, he said, if UN road convoys are denied access to areas, the ISSG will mandate "the World Food Program to immediately carry out ... Air bridges and air drops."
Lavrov did not dispute Kerry's account of the agreement, but said Moscow's emphasis was on the fight against the Islamic State group and others he deemed terrorists.
"We don't support Assad, we support the fight against terrorism," he said, stressing that the strongman is the leader of a recognised UN member state.
"On the ground we don't see any more real and efficient force than the Syrian army, even given all its weaknesses.
