VIENNA -- The United States, Russia and more than a dozen other nations have directed the UN to begin a new diplomatic process with Syria's government and opposition with the goal of reaching a nationwide cease-fire and political transition.

U.S. Secretary of State John Kerry made the announcement at a joint news conference with Russian Foreign Minister Sergey Lavrov and the UN envoy to Syria, Staffan de Mistura.

Kerry made no declarations about the future of Syrian President Bashar Assad. Russia and Iran back Assad; the U.S. and its allies want him ousted.

Kerry said the UN-led process should lead to a new constitution for Syria and internationally supervised elections.