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.
The Western-backed Syrian opposition coalition has agreed to participate in international peace talks in Geneva, Reuters reports.
President Assad's British-born wife has made a rare public appearance, visiting primary school children in Damascus, according to official images released by Syria's national news agency.
It comes just two days after a fatal air strike on a rebel-held suburb of Damascus that left two children orphaned.
Syrian President Bashar al-Assad has sent Pope Francis a private message, the Vatican said on Saturday, without disclosing its contents.
According to Reuters, it was the first known time Assad has sent a direct message to the pontiff since the start of Syria's civil war in 2011. Pope Francis has made numerous appeals for an end to the conflict, the latest on Christmas Day.
Vatican sources said the message likely included the Syrian government's position ahead of peace talks due to start on January 22 under UN auspices in Geneva. According to the Syrian presidency Twitter account, Assad called for peace through dialogue.
The Vatican said a delegation headed by Joseph Sweid, a Syrian minister of state, held talks in the Vatican with the pope's secretary of state, Archbishop Pietro Parolin and his foreign minister, Archbishop Dominique Mamberti.
"The delegation brought a message from President Assad for the Holy Father and illustrated the position of the Syrian government," a statement said.
Syrian president Bashar al-Assad has suggested he will seek re-election next year despite the country's ongoing bloody civil war.
"Personally, I don't see any obstacles to being nominated to run in the next presidential elections," TV station Al Mayadeen quoted him as saying in an interview.
Syria's President Bashar al-Assad has said he will respect United Nations accords onchemical weapon, Reuters reports, citing an interview with Italian television,
The UK must wait to receive details of Syria's chemical weapons stockpiles that have been received by an international watchdog.
The Organisation for the Prohibition of Chemical Weapons (OPCW) confirmed it had received the "expected disclosure" from the Syrians and was "currently reviewing the information".
The Foreign Office, though, said the "unique case" of Syria has forced a delay:
– Foreign Office spokesman
It has made this disclosure as a non-state party. The coming OPCW executive council needs to endorse a new process to handle Syria's chemical weapons.
Once this has been achieved, the OPCW will be in a position to make the Syrian disclosure available to states' parties.
In consultation with partners we will reach a judgment on its credibility. This is only the start of a long and complex process.
The Organisation for the Prohibition of Chemical Weapons (OPCW) says it has received the "expected disclosure" from the Syrian government.
We can confirm that we have received the expected disclosure from the Syrian government regarding its chemical weapons programme. 1/2
The Technical Secretariat is currently reviewing the information received. 2/2
Syria had util the end of today to submit full details of its chemical weapons programme to the international watchdog to comply with an agreement with Russia and the US.
Syria has until the end of today to submit full details of its chemical weapons programme to an international watchdog as part of a deal brokered with Russia and the US.
The Organisation for Prohibition of Chemical Weapons (OPCW) confirmed it has received an "initial disclosure" from Syria
Syria is believed to have around 1,000 metric tonnes of chemical toxins and has agreed to destroy them by the middle of next year under the Russian-US proposal.
UN director for Human Rights Watch has said he hoped the debate on Syria that he expects to take place in the General Assembly will serve as a "wake-up call" for the Security Council, which has been deadlocked over a resolution to chemical weapons use.
"There's no denying that there is particular urgency this year for the General Assembly", said Philippe Bolopion.
"It will not address the overall situation. Only maybe one or two percent of the 100,000 people who've been killed in Syria over the last two and a half years have been killed with chemical weapons. The rest of the people have died at the hands of conventional weapons", he added.
The Organisation for the Prohibition of Chemical Weapons will only say they have received some documentation and that there is more to come
Under the terms of that plan agreed by the US and Russia, the Assad government must provide a comprehensive list of the nature and location of all of its chemical weapons by the end of tomorrow.
Chemical weapons are very much the ugly crown jewels in the Assad defence set-up. His father spent decades building them up in response to the Israeli nuclear threat.
You look at the last ten years of history in the Middle East, what happens to dictators who surrender their weapons of mass destruction or even elect inspectors into having a look at them. If Assad was in a position of strength, he would not be giving up one drop of his nerve agent.