The talks don't officially start for another day....but the US secretary of state has already arrived in ViennaHe's expected to attend pre-meetings on Thursday evening ....Before Friday's talks begin on finding a political solution to Syria's four and a half year war The key players are divided on what to do about Bashar al Assad...Russia and Iran insist the syrian president should not be forced to leave power The United States, Saudia Arabia and Turkey want him to goBut the US has recently said it could tolerate a short transition period with Assad, providing he eventually steps downAssad's political future has long been a major obstacle to building an international consensusThese talks, however, will differ from previous ones: for the first time, Iran will be at the tableEven arch regional rival saudi arabia - which backs rebel groups in Syria - has accepted Iran's presence4. SOUNDBITE (English) Adel bin Ahmed Al-Jubeir, Saudi foreign minister: "We have differences that remain with Russia and with Iran with regards to how and when Bashar Al-Assad leaves. So the view of our partners in this was that we should test the intentions of the Iranians and the Russians about their seriousness in arriving at a political solution in Syria which we all prefer." Iran is believed to be financially propping up assad's government, helping his soldiers and subsidising weaponsDespite reports hundreds of iranians are fighting in syria, iran denies sending in combat troops.

Who's who in Vienna talks

The talks don't officially start for another day....but the US secretary of state has already arrived in ViennaHe's expected to attend pre-meetings on Thursday evening ....Before Friday's talks begin on finding a political solution to Syria's four an