A report by leading international lawyers accuses Syria of systematic torture. A warning that this article contains graphic images.
Food supplies have begun entering a besieged suburb of the Syrian capital Damascus.
John Kerry said the UN report into the Syria chemical attack clearly shows the US were right that Assad was the perpetrator.
US Secretary of State John Kerry said there was "no way" president Bashar al-Assad can be part of a transitional government in Syria.
Kerry added that Assad cannot regain legitimacy to govern and the Geneva peace talks will be "tough and complicated".
Syria's President Bashar al-Assad said it is "totally unrealistic" for opposition coalition members to become ministers in the government, during an interview with AFP.
Syria's President Bashar al-Assad has said there is a "significant" chance he will stand in the next presidential election, despite opposition and international calls for him to step down.
He told AFP news agency, "I see no reason why I shouldn't stand? (if) there is public desire.....in short, we can say that the chances for my candidacy are significant."
Syria's President Bashar-al-Assad has told AFP news agency, he is likely to seek a new term.
AFP #Exclusive: Syria's Assad: 'Significant' chance I'll seek new term
Syria's President Bashar al-Assad said he is not ready to give up power and the issue is not up for discussion at the Geneva peace talks next week, Interfax reports.
He reportedly told Russian parliamentarians: "If we wanted to give up, we would have done so at the very beginning. We are on guard for our country. This issue is not up for discussion."
William Hague has voiced his support for the Syrian National Coalition's decision to attend peace talks next week aimed at ending the country's bloody civil war.
The foreign secretary said the western-backed group hold a "vision of a democratic and pluralist Syria."
– Foreign Secretary William Hague
The National Coalition reached this difficult decision against the backdrop of continued brutal regime attacks on Syrian civilians, and the deliberate blocking of humanitarian aid.
The UN Secretary General has made clear that the aim of the talks is to agree a political transition and an end to the conflict. In contrast to the National Coalition, the Syrian regime has still not agreed to this aim.
As I have said many times, any mutually agreed settlement means that Assad can play no role in Syria's future.
The main Syrian political opposition group in exile, the Syrian National Coalition, said it had agreed y to attend internationally sponsored peace talks beginning in Switzerland next week.
The "Geneva 2" talks with representatives from President Bashar al-Assad's government start in Montreux on Wednesday and are seen as the most serious international effort yet to end the near three-year conflict.
The Western-backed Syrian opposition coalition has agreed to participate in international peace talks in Geneva, Reuters reports.