BEIRUT (Reuters) - A senior Syrian opposition official accused Russia on Friday of procrastinating and showing no seriousness in the first talks it has held with rebel groups from the Syrian city of Aleppo, indicating meetings in Turkey are getting nowhere.

Russia is Syrian President Bashar al-Assad’s most powerful ally, and its air force has been attacking rebel-held areas in Syria since September, 2015, including eastern Aleppo where the government its allies have seized large areas from insurgents.

The rebels entered the talks with senior Russian officials about two weeks ago in an effort to secure aid deliveries and a lifting of the siege on eastern Aleppo, the official said.

“There is severe procrastination by the Russians,” the official said, speaking on condition of anonymity due to the secret nature of the meetings.

“There is absolutely no seriousness, so if the European states and the United States do not intervene we will face real tragedy, if matters continue at the same pace,” the official added. Turkey, a major sponsor of the rebels, has been acting as a guarantor in the meetings.