President Barack Obama and U.N. Secretary-General Ban Ki-moon are sounding different tones on Syria today.

In remarks to the U.N. General Assembly, Obama pledged U.S. support for Syrians trying to oust President Bashar Assad -- calling Assad "a dictator who massacres his own people."

But in his own speech earlier, the U.N. chief emphasized ending Syria's civil war. The secretary-general said, "We must stop the violence and flows of arms to both sides" -- and bring about a "Syrian-led transition as soon as possible."

Obama didn't issue a call for an end to the violence -- though he made no mention of arming the opposition. And he stressed the importance of making sure that "what began with citizens demanding their rights does not end in a cycle of sectarian violence."

Russia and China have vetoed three Western-backed resolutions aimed at pressuring Syria's Bashar Assad to end the violence and enter negotiations on a political transition.

The secretary-general said the situation in Syria is worsening every day, and that it's a serious and growing threat to international peace and security that requires action from the Security Council.