By Michelle Nichols

UNITED NATIONS, June 30 (Reuters) - United Nations Syria mediator Staffan de Mistura will brief Secretary-General Ban Ki-moon next week on his talks with Syria's warring parties and world powers on how to end the country's four-year conflict, a U.N. spokesman said on Tuesday.

"Syria is on the brink of falling apart, putting at even further risk what is already the most unstable region in the world," Ban said in a statement to mark the third anniversary of a Syria roadmap for peace called the Geneva Communique.

The June 2012 document called for political transition but left the role of Syrian President Bashar al-Assad unresolved.

"Three years after the parties themselves, and all those with influence on them, expressed support for a plan to end that suffering, it is time to find an exit from this madness," Ban said.

Some 220,000 people have been killed in Syria and 12.2 million people need help, including more than 5 million children, the United Nations says. About 7.6 million are internally displaced and more than 4 million have fled Syria.

De Mistura - whose two predecessors resigned in frustration at the failure to make headway in ending the Syrian war - has spent the past two months holding consultations with the warring parties, world and regional powers.

U.N. spokesman Farhan Haq said de Mistura would brief the secretary-general later next week after Ban returns from a visit to Norway on Thursday. De Mistura is currently scheduled to brief the U.N. Security Council in late July.

A Syrian government crackdown on a pro-democracy movement in 2011 led to an armed uprising. Radical Islamic State militants have taken advantage of the chaos to declare a caliphate in territory they have seized in Syria and neighboring Iraq.

The 15-member U.N. Security Council has been largely deadlocked on how to end the war.

The council failed last year to refer the Syrian conflict to the International Criminal Court for war crimes and crimes against humanity. Syrian ally Russia, backed by China, vetoed the move and three other resolutions threatening Assad's government with sanctions.



(Reporting by Michelle Nichols; Editing by Cynthia Osterman) ((michelle.nichols@thomsonreuters.com; +1 646 223 6117; Reuters Messaging: michelle.nichols.reuters.com@reuters.net; Twitter: @michellenichols))