Syria ceasefire
Russian Foreign Minister Sergei Lavrov, US Secretary of State John Kerry and UN Special Envoy for Syria, Staffan de Mistura (L-R) speaking after the International Syria Support Group (ISSG) meeting in Munich, Germany, REUTERS/Michael Dalder

World powers meeting on Syria have agreed to seek a nationwide "cessation of hostilities" within a week, US Secretary of State John Kerry announced, but admitted that the plan was "ambitious". The ceasefire however does not include the fight against jihadist groups Islamic State or Isis and al-Nusra Front, he said.

Speaking alongside his Russian counterpart Sergei Lavrov and the UN special envoy for Syria Staffan de Mistura, he said the world powers have also agreed to immediately push for and expand the delivery of humanitarian aid in Syria.

They were speaking at a news conference after the International Syria Support Group (ISSG) meeting in Munich, Germany. In admitting that the ceasefire plan was "ambitious", Kerry said the real test would be whether all parties involved honoured the commitments made. "What we have here are words on paper, what we need to see in the next few days are actions on the ground," he said.

The move comes as the Syrian army, backed by Russian air strikes has been making advances in the Aleppo province. The move by the Syrian army and Russia will put the lives of tens of thousands of civilians in rebel-held parts of the major city of Aleppo.

Lavrov however was a bit more optimistic, saying that there were "reasons to hope we have done a great job today." A UN task force will be set up to ensure humanitarian access is granted to all sides, Kerry added.