U.N. Secretary-General Ban Ki-Moon for the first time is calling for the situation in Syria to be referred to the International Criminal Court.

In his state of the world address to leaders from the U.N.'s 193 member states, Ban says "innocent Syrians pay the price of more barrel bombs and terrorism" and there must be no impunity for "atrocious" crimes.

His call opened the annual General Assembly gathering of world leaders that includes addresses from President Barack Obama, Russian President Vladimir Putin and Chinese President Xi Jinping on Monday morning alone.

Ban says five countries "hold the key" to a political solution to Syria: Russia, the U.S., Saudi Arabia, Turkey and Iran.

The U.N. chief says the Syrian conflict is "driven by regional powers and rivalries."