"This is really quite the conundrum (Russian President Vladimir) Putin has to solve," said Sascha Bruchmann, a military analyst at the London-based International Institute for Strategic Studies.There is much at stake for Russia — if Assad's regime falls, Russia will lose its regional foothold in the Middle East, including its only naval base in the Mediterranean, and its regional and global influence will be diminished.But propping up Assad and defending the Syrian capital of Damascus from any rebel advance will require military support that Moscow may not be able to spare when the vast bulk of its forces are fighting in Ukraine."Russia is stretched thin so the costs to intervene are high, and the geopolitical benefits may be smaller than (when it first intervened in the Syrian Civil War in 2015)," Bruchmann added.Russian, Syrian jets intensify bombing campaigns in rebel-held territory of Syria, Reuters reportsRussian and Syrian fighter jets have struck the rebel-held city of Idlib on Dec.