Syrian rebel leaders have guaranteed the security of Russian military installations in the country, as well as diplomatic buildings, Russians briefed on the situation said Sunday. Russia has maintained a naval hub at the Mediterranean port of Tartus and the Khmeimim air base in northwestern Syria since Moscow's military helped President Bashar al-Assad claw back the majority of the country, after nationwide protests that erupted in 2011 threatened his rule. The fall of the Assad regime threatens to limit Russia's ability to project power in the Middle East. Russian state media reported Sunday that Assad had been granted asylum in...