The talking is still a long way from a solution, while the killing continues
The United States, Russia and more than a dozen other nations have directed the UN to begin a new diplomatic process with Syria's government and opposition with the goal of reaching a nationwide ceasefire and political transition.
US Secretary of State John Kerry made the announcement at a joint news conference with Russian foreign minister Sergey Lavrov and the UN envoy to Syria, Staffan de Mistura.
Mr Kerry made no declarations about the future of Syrian president Bashar al-Assad. Russia and Iran back Assad, but the US and its allies want him ousted.
Mr Kerry said the UN-led process should lead to a new constitution for Syria and internationally supervised elections.
The talks in Vienna came as a barrage of missiles slammed into a crowded suburb of the Syrian capital, killing at least 45 people.
The attack in the Damascus suburb of Douma was a stark reminder of the enormous civilian suffering inside Syria while negotiations take place.
There were conflicting reports about the attack in Douma. The Syrian Observatory for Human Rights and the Local Co-ordination Committees said government forces fired more than 11 missiles at a market. The Observatory said the attack killed 57 people, while the LCC said at least 40 died.
It was also announced yesterday that the US is to send dozens of special forces soldiers to Syria in the first sustained commitment of US troops on the ground there in the fight against Islamic State.
They will be deployed to northern Syria, where they will "advise and assist" Kurdish and Arab forces.
President Obama approved the move yesterday. US special forces have been deployed in Syria before on one-off, secretive missions but this will be the first time they have been permanently stationed inside the country.
It marks a significant escalation, which the White House said was "consistent with the strategy to intensify the battle against Isil".
The special forces will work with the Syrian Arab Coalition along the Syrian border, including helping to co-ordinate air strikes.
They are not expected to be fighting on the front lines and will provide "training, assistance and advice" in the same way US troops are already doing to anti-Islamic State forces in Iraq.
A US official said there was "no intention of engaging in long-term, large-scale combat operations" in Syria.
Last week saw the first death of an American serviceman in action in Iraq since 2011.
Master Sergeant Joshua Wheeler died in a firefight as US special operations soldiers and Kurdish forces freed 70 hostages from an Isil prison near Hawija.
The number of special forces being deployed in Syria will be "fewer than 50", according to a US official.
In Washington, Mac Thornberry, the chairman of the House of Representatives Armed Services Committee, said that an intensified US effort to combat Islamic State militants in Syria was "long overdue."
However, Mr Thornberry, a Republican, said he still sees a lack of what he termed a "coherent" strategy from the administration of Democratic President Obama.
"I do not see a strategy for success; rather, it seems the administration is trying to avoid a disaster, while the president runs out the clock," he said.
The talks in Vienna had brought together 17 countries with starkly different views of Syria's conflict. Mr Kerry, sat alongside Sergei Lavrov, the Russian foreign minister, at the head of the negotiating table. But the countries represented in Vienna are as yet divided over the future of President Assad. The Arab powers, along with America and the West, believe that Assad's departure is the essential condition for peace in Syria; Russia and Iran, meanwhile, insist that he must stay, at least for a transitional period.
How long such a transition would last - and how an election might be held at the end of it - will be key issues for the talks in Vienna.
As he arrived in Austria's capital, Philip Hammond, the British Foreign Secretary, played down expectations, describing the conference as an "exploratory discussion".
He added: "We're gathered here this morning to see if there is any scope for bridging the gap we know exists between the Russian-Iranian position on the one hand and the position of most of the rest of the countries represented on the other."
Saudi Arabia and the other Gulf states were bitterly opposed to including Iran. They believe that Iran's support for Assad - which has included sending thousands of Hezbollah fighters and members of the Revolutionary Guard Corps into Syria - serves only to inflame the war and amounts to unwarranted interference in the Arab world.
America and Britain once shared this view, but they have since decided that Iran's direct influence in Syria means that Tehran must be part of any settlement.
Under pressure from the West, Saudi Arabia reluctantly agreed to attend the conference with Iran.
As talks began, Assad's regime carried out one of its bloodiest attacks for month. Rockets exploded in the crowded market in Douma. Human rights groups have accused Assad of deliberately trying to drive civilians from rebel-held areas by targeting markets and hospitals.
This strategy has been most evident in Douma and other towns along the industrial belt north of Damascus, which have suffered poison gas attacks as well as barrel bombs. In August, 117 people were killed during a single day of air strikes in Douma.
Separately yesterday, two Syrian activists, including one belonging to a collective that reports on Islamic State atrocities were found slain in a city in southern Turkey.
The Raqqa-based activist collective - called 'Raqqa is Being Slaughtered Silently' - did not say when Ibrahim Abdul-Qadir and Fares Hamadi were killed. It blamed Isil for the killings, which took place in the city of Sanliurfa. Another Syrian activist group, the Local Co-ordination Committees, said the two were known activists from Raqqa. There was no immediate comment from Turkish authorities.
Islamic State militants captured Raqqa in northern Syria two years ago and the city later became the de facto capital of Isil's territory.
An activist with the group refused to speak about the killings of the two activists, saying only: "Our wound is still fresh."