RIYADH, Saudi Arabia — Saudi Arabia urged top European diplomats at a gathering Sunday to lift sanctions against Syria to boost rebuilding the country and its economy after last month’s overthrow of President Bashar Assad.

European and Middle Eastern diplomats met here in the Saudi capital to discuss Syria’s future. The U.S. and European countries have been wary over the Islamist roots of Syria’s new rulers — the former insurgents who drove Assad out of power — and have said…