Iranian President Mahmoud Ahmadinejad and his Syrian counterpart Bashar al-Assad discussed improved cooperation at the start of a two-day summit in Tehran Saturday, state television network IRIB reported. The two presidents explored ways to strengthen and expand bilateral and international cooperation "as a means of maintaining regional stability and security," IRIB reported. The two sides also voiced their readiness to increase annual trade volumes from the current 340 million to 640 million dollars.