BEIRUT (Reuters) - Five Western and Arab states that have backed the rebellion against Syrian President Bashar al-Assad make no reference to his future in a document proposing changes to U.N.-led talks, an apparent recognition of his strong position in the conflict.

Syrian President Bashar al-Assad as seen in Damascus, Syria November 14, 2017. SANA/Handout via REUTERS

The document drawn up by the United States, Jordan, Britain, France and Saudi Arabia made recommendations to the U.N. Syria envoy Staffan de Mistura for what they called a “practical approach” to what would be a “slow” political process.

It leaked on Friday as the latest round of U.N.-led talks was underway in Vienna, and its authenticity was confirmed to Reuters by three diplomatic sources.

The Syrian government’s negotiator at the Vienna talks dismissed the proposals as “totally unacceptable”. A Syrian opposition official, speaking to Reuters on condition of anonymity, said it was “not good”, declining to explain why.

Assad appears unassailable in the conflict thanks to direct military intervention by Iran and Russia, which is now seen as the pivotal foreign power in the war and is due to host a Syrian peace congress in Sochi next week.

The five states’ proposals recommend that de Misutra focus the parties on reforming the constitution, on holding U.N.-supervised elections for Syrians inside and outside the country, and creating a “safe and neutral environment” for the vote.

“All external supporters of the political process should encourage the opposition and government delegations to engage genuinely in the talks, focus squarely on these topics and, at least initially, set aside other issues,” it said.

While not addressing Assad’s fate, the proposals call for a new constitution that would dilute presidential powers in favor of a stronger parliament.

It also calls for the departure of all foreign militias - an apparent reference to the Iran-backed Shi’ite groups that have provided critical support to Assad - before elections.

A European diplomat confirmed the paper had been presented to de Mistura.

The United Nations has sponsored eight rounds of fruitless peace talks in Geneva since the war began in 2011, a conflict that has killed hundreds of thousands and driven millions from their homes while dragging in world and regional powers.

U.S. Secretary of State Rex Tillerson in a Jan. 17 speech called for “patience” on Assad’s departure, another acknowledgement that Russian and Iranian backing for Assad means he is unlikely to leave power soon.