United Nations Special Envoy for Syria Staffan de Mistura attends a news conference during the Intra Syria talks at the United Nations Offices in Geneva, Switzerland, May 19, 2017. REUTERS/Pierre Albouy

VIENNA (Reuters) - The United Nations special mediator for Syria, Staffan de Mistura, wants to start a fresh round of talks between Syrian factions on July 10, his office said on Saturday.

Since a resumption of negotiations last year, there have been multiple rounds brokered by the United Nations between representatives of Syrian rebels or the government of Bashar al-Assad, resulting in scant progress.

“(De Mistura) wishes to announce he will convene a seventh round of the intra-Syrian talks in Geneva. The target date for arrival of invitees is July 9, with the round beginning on July 10,” it said in an emailed statement.

“He intends to convene further rounds of talks in August and in September.”

De Mistura said earlier this week such talks would depend on the progress made in setting up “de-escalation” zones in Syria, where over six years of conflict have killed more than 400,000 people.

The Russian Foreign Ministry said on Tuesday that talks between Russia, Turkey and Iran to discuss these zones would take place in the Kazakh city of Astana in early July.

Russia and Iran back Assad against rebels supported by Western powers, while both sides, aided by Sunni powers such as Saudi Arabia, fight against Islamic State militants.