More than 60,000 people have died in Syria as a result of war that grew out of the so-called Arab Spring in early 2011. U.N. Secretary-General Ban Ki-moon told the Council on Foreign Relations that Syria was on the verge of collapse.
"Syria is self-destructing," he said.
Syrian President Bashar Assad has remained defiant as fighting enters Damascus. The U.N. Security Council has been unable to censure the government for the bloodshed in part because of Russian concerns that draft resolutions lack balance.
"The Security Council must no longer stand on the sidelines, dead-locked, silently witnessing the slaughter," Ban said. "It must be willing, at long last, to come together and establish the parameters for the democratic transition that could save Syria."
Opposition leader Ahmad Moaz al-Khatib said he would enter discussions with Assad's government only if it released 160,000 political prisoners. He told al-Arabiya that Assad could appoint Vice President Farouk al-Shara as his emissary because Shara's hands weren't "stained with blood."
Ban is to meet this week with U.S. Secretary of State John Kerry and other government officials in Washington.