Turkey-Russia jet downing: Moscow beefs up defences in Syria
Russia has strengthened its anti-aircraft defences in Syria by moving a cruiser towards the coast and deploying new missiles at its main base.
The Moskva cruiser's long-range air defence system will provide cover for Russian aircraft, as will the S-400 missiles which arrived on Thursday.
The row over Turkey's downing of a Russian combat jet on Tuesday rages on.
Turkish President Recep Tayyip Erdogan has warned Russia not to "play with fire" with its operations in Syria.
Russia has suspended its visa-free arrangement with Turkey and is planning to introduce a wide range of economic sanctions. President Vladimir Putin wants an apology from Turkey before he will speak to Mr Erdogan.