The UN-led peace talks, dubbed Geneva II, broke down on February 15 when a second round ended with no new date set for them to reconvene.
Syria's government and opposition began talks on January 22, with the participation of dozens of nations, including Russia, which backs the regime of President Bashar al-Assad, and the United States, which supports the opposition.
"The Secretary General appeals to the region and the international community and in particular to the Russian Federation and the United States, as the initiating states of the Geneva Conference on Syria, to take clear steps to reenergize the Geneva process," Ban said in a statement issued through his spokesman.
Ban also "strongly urges the Syrian government and opposition to exercise responsibility, leadership, vision and flexibility to rise to the challenge," the statement said.
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Working with Brahimi, "the Syrian sides and regional and international actors must act now to bring the tragedy in Syria to an end."
With more than 140,000 lives lost since an uprising against Assad's regime began in March 2011, Ban called the situation in Syria "the biggest humanitarian and peace and security crisis facing the world."
"The Secretary General deeply regrets the inability of the international community, the region and the Syrians themselves to put a stop to this appalling conflict," he said.