UN begins round of Syria peace talks in Geneva

De Mistura and the HNC delegates appeared grim-faced and tense as they began the session, remaining silent while a Reuters camerawoman filmed the opening moments of the session.

A Syrian government delegation is expected to arrive on April 15.

The previous round ended on March 24 with de Mistura promising to hone in on the divisive question of Syria's political transition when the warring parties returned to Geneva.

Since then he has met officials in Moscow, Damascus and Tehran to gather opinions about the way forward, while Syria's partial ceasefire has been tested by a flare up in fighting and Syria's government has held a parliamentary election which it called a show of support for President Bashar al-Assad.