World and regional powers working to end the Syrian conflict vowed to bolster the country's shaky ceasefire Tuesday but failed to set a new date for peace talks, AFP reports.

US Secretary of State John Kerry said the International Syrian Support Group (ISSG) had agreed there would be "consequences" for parties breaching the ceasefire 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" (ISIS) terrorist group and that Moscow would support it.