PARIS (Reuters) – France dismissed on Thursday any suggestion that millions of Syrian refugees could start returning home, as urged by Russia, which backs President Bashar al-Assad.

Foreign ministry spokeswoman Agnes von der Muhll said the conditions for a return have not been met, given Assad’s treatment of those who have already gone home and a possible offensive on rebel territory in northern Syria.

In recent weeks Russia has called on Western powers opposed to the Syrian government to help refugees return home and aid reconstruction of areas under his control.

However, Von der Muhll cited a decree depriving refugees and internally displaced people of their properties, the instability of the country and cases of arrest and forced conscription of Syrians returning from Lebanon.

“To consider a return of the refugees is illusory, in the current conditions,” she said.

The seven-year civil war has killed an estimated half a million people, driven 5.6 million out of Syria and displaced around 6.6 million within the country.

Most refugees are from the Sunni Muslim majority, and it is unclear whether Assad’s Alawite-dominated government will allow all to return freely or whether they would want to. Sunnis made up the bulk of the armed opposition to Assad.

France, which backs the opposition, says it will not support reconstruction of areas under Assad’s control until there is a negotiated political transition under U.N. auspices.

“This year has seen the largest movement of displaced people since the beginning of the conflict and … the entire international community has warned of the risks of a major humanitarian and migratory crisis in the event of an offensive against the province of Idlib,” Von der Muhll said.

The Idlib region, a refuge for civilians and rebels displaced from other areas of Syria as well as jihadist forces, was hit by air strikes and shelling last week, in a possible prelude to a full-scale government offensive.

(Reporting by John Irish; editing by David Stamp)