RIYADH — Three Syrian opposition camps met in Riyadh Monday to try to forge a unified front for what the UN hopes will be a substantive round of peace negotiations in October.

The Saudi-backed opposition High Negotiations Committee (HNC) held an hours-long meeting in a Riyadh compound with delegations from two other moderate camps, the so-called Cairo and Moscow groupings.

UN Syria envoy Staffan de Mistura has sought to unify the opposition to develop a more pragmatic negotiating strategy after hosting seven rounds of largely unsuccessful talks.

The main obstacle has been the fate of President Bashar Al-Assad, with the HNC insisting on his ouster but the other two camps adopting a softer stance on the issue.

"The goal of the meeting is to arrive at an agreement on the political program that forms the basis of the negotiations. At the forefront is the position on Bashar al-Assad," Syrian opposition leader Ahmed Ramadan told AFP this week.

There was no immediate comment on the conclusion of Monday's meeting.

De Mistura said last week that he hopes for "real, substantive" peace talks between the government and a still-to-be-formed unified Syrian opposition in October.

Rebels have suffered heavy territorial losses since peace talks to end the war began, including the regime's recapture of Aleppo, a former opposition stronghold.

With the rebel fighting position weakened, experts say the regime faces no pressure to make concessions at the negotiating table, and especially not over the question of Assad's future.

De Mistura has said he may still try to organise another "preparatory" round of talks in Geneva next month, but stressed that his office will be focusing on the agenda for "substantive talks" aimed for October. — AP