MOSCOW (Reuters) - Saudi Arabia is working closely with Russia on uniting Syria s opposition, Saudi Foreign Minister Adel al-Jubeir said on Thursday, adding that Moscow and Riyadh agreed on the need to preserve Syria s territorial integrity and state institutions. Speaking at a news briefing after Saudi King Salman s meeting with Russian President Vladimir Putin in the Kremlin, Jubeir also said that both Russia and Saudi Arabia believe in the principle of non-interference in other countries  internal affairs and in the principle of territorial integrity.  