Damascus said the foreign-backed opposition’s refusal to sign a declaration condemning “terrorism” in Syria is "a stain" on the group.
On Saturday, Syrian Foreign Minister "Walid al-Muallem" made the remarks on the plane back home from 10 days of talks in the Swiss cities of Montreux and Geneva on the crisis in Syria.
Muallem said the Syrian government delegation had agreed to discuss everything during the Geneva talks, but the opposition refused to address the issue of terrorism and threatened to derail talks.
The Geneva-2 talks kicked off in the Swiss town of Montreux on January 22. Syrian government and foreign-backed opposition as well as dozens of nations participated in the event.
Syria has been gripped by deadly unrest since 2011. According to reports, the Western powers and their regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants operating inside the country.
The United Nations says more than four million Syrians will be forced out of their homes in 2014 by the escalating conflict in the country that has killed more than 100,000 people and displaced millions so far.