President Vladimir Putin has signed a law ratifying a deal with the Syrian government allowing Russia to keep its air base in Syria for almost half a century, official documents show. The original deal, signed in Damascus in January, sets out the terms under which Russia can use its Hmeymim air base in Latakia Province which it has used to carry out air strikes against forces opposing President Bashar al-Assad. The base has been at the heart of Moscow’s military foray since it intervened in the conflict in September 2015, helping turn the tide in favour of Assad, one of Russia’s closest Middle East allies.