US Secretary of State John Kerry says a transitional government for Syria is to be set in six months’ time and elections in 18 months, according to the Associated Press.

America’s top diplomat reportedly made the comment at the end of the latest round of international talks on the Syrian crisis in Vienna, Austria.

Kerry said parties to the Syria talks agreed on Saturday to accelerate efforts to end the conflict in the Arab country by launching negotiations between the government and opposition by January and holding elections within 18 months, Press TV reports.

He told a news conference after the Vienna talks that the five permanent members of the UN Security Council also agreed to pass a resolution in favor of a ceasefire in Syria.

Kerry noted, however, that a Syria ceasefire does not apply to terrorist groups like Daesh (ISIL) or the al-Qaeda-linked al-Nusra Front and other extremist groups.

He added that the international negotiations still reached no agreement on the future of Syrian President Bashar al-Assad despite concrete progress in their talks on ending the Syrian conflict.

US Secretary of State John Kerry (L), United Nations Special Envoy for Syria Staffan de Mistura (C) and Russia's Foreign Minister Sergei Lavrov (R) address the media after the meeting in Vienna, Austria, on November 14, 2015. AFP PHOTO

"We still differ on what happens to Bashar al-Assad," Kerry told reporters at the joint news conference with Russian Foreign Minister Sergei Lavrov and UN special envoy Staffan de Mistura.

Earlier, European Union foreign policy chief Federica Mogherini described as "very good" the latest round of talks on the Syrian crisis.