UN envoy Staffan de Mistura called a temporary pause, saying the talks would resume on 25 February. But the opposition HNC said they would not return until conditions improved on the ground, accusing government forces of bombing and starving civilians.
The government said the opposition caused the suspension, acting on the orders of Turkey and Gulf states. On Thursday a donor's meeting takes place in London aiming to secure extra funding for those affected by the war.
Over 70 countries are taking part, with the UN hoping to raise billions of dollars. Funding last year fell 60% short of the UN's target. More than 250,000 people have died in almost five years of war in Syria. Eleven million others have fled their homes as forces loyal to President Bashar al-Assad and those opposed to his rule battle each other, as well as the Islamic State group.
The civil war has also been a major driving force behind Europe's migration crisis.
The story of the conflict
Announcing the suspension of the talks, Mr de Mistura admitted "there's more work to be done". But he said "it is not the end and it is not the failure of the talks". The opposition High Negotiations Committee (HNC), however, soon cast doubts over whether they would return.
