"It is imperative that the U.N. Security Council assume its responsibilities and force the implementation of its resolutions for a ceasefire, to protect the Syrian people from killing and displacement," Khalid al-Attiyah told participants in the Doha Forum.
He accused
Hereditary President-for-Life Bashir Pencilneckal-Assad
Scourge of Qusayr...
's government of using "poison gas, in a flagrant challenge to the international community and in violation of international laws".
Qatar is a major backer of the rebellion against Assad.
More than 150,000 people have been killed in Syria's conflict, which began in mid-March 2011 with anti-government protests.