Tehran (AFP) - A top Iranian official said Sunday several countries involved in Syria peace talks had tried to exclude President Bashar al-Assad from future elections but Tehran insisted the demand be withdrawn.

The remarks came after officials said agreement was reached on a roadmap to a more inclusive government in Damascus in the next six months aimed at ending Syria's conflict, with polls to follow one year later.

The peace talks involving 20 countries and organisations meeting in Vienna however remained deeply divided on the future of Assad, whose main regional ally has been Iran.

A final statement after Saturday's meeting said the goal was to bring Syrian government and opposition representatives together by January 1, but the political process would require a ceasefire.

It failed to breach the divide over Assad, however, and Iran's deputy foreign minister Hossein Amir Abdollahian went further by saying only the Syrian president could decide on whether to contest future polls.

"Some participants insisted that the sidelining of Bashar al-Assad be included in the text, but the Islamic Republic of Iran did not allow this issue to be mentioned in the final declaration," he told state television.

"We have insisted that only Bashar al-Assad may decide to take part or not in the elections and only the Syrian people can vote or not vote for him," he added.

The talks in Vienna took on new urgency after Friday's devastating attacks in Paris, claimed by the Islamic State jihadist group, killed at least 129 people. IS said the attacks were in response to French policies on Syria.

Vowing France would not stop its "international action", Foreign Minister Laurent Fabius said the Paris killings underlined the need to "increase the international coordination in the struggle against Daesh," referring to IS by its Arabic acronym.

The countries gathered in Vienna agreed Syria's next elections be held under a new constitution and be administered by the United Nations with the diaspora allowed to vote.

Western and Arab countries want Assad, who has been fighting an uprising since 2011, removed to allow what they say would be a transitional government that can unite the country.

But Russia, carrying out air strikes against Syrian rebels since late September, is sticking by Assad along with Iran.

Iran has provided Syria, an Arab state ruled by Assad's minority Alawite sect, a Shiite offshoot, with financial aid and military advisers from its elite Revolutionary Guards Corps.

The two countries have been close allies since Syria, then ruled by Assad's father Hafez, sided with Tehran against the later executed Iraqi dictator Saddam Hussein in the 1980-1988 Iran-Iraq war.

By AFP