BEIRUT/VIENTIANE, REUTERS, Jan 25, 2016–  Syrian peace talks meant to begin this week were stalled on Monday partly over the question of who would represent the opponents of Bashar al-Assad.

U.S. Secretary of State John Kerry said he expected clarity within a day or two.

The talks were meant to begin on Monday in Geneva, but have been held up by international disagreement over who should be invited from the opposition. Rebels also want an end to air strikes and government sieges of territory they hold, and the release of detainees.

Diplomacy has so far yielded no progress toward ending or even curbing Syria’s civil war, which has killed more than 250,000 people and driven more than 10 million from their homes.

The main Sunni Arab opposition groups, who are supported by Arab governments and the West, say they will not attend unless they can choose their own delegation. Spokesman Salim al-Muslat said the opposition High Negotiation Committee (HNC) would discuss its position on Tuesday.

Kerry said he backed U.N. envoy Staffan de Mistura in holding off on issuing invitations until things are clearer.

“We will have to see what decision Staffan makes as to exactly how he is going to begin; but we don’t want to decide and have it crumble on day one. It’s worth taking a day or two, or three, or whatever,” Kerry said during a visit to Laos.

The war has ground on for years with no side close to victory.

Opposition spokesman Muslat accused Russia and the Syrian government of throwing obstacles in the path of the talks.

The HNC, formed in Saudi Arabia last month and grouping armed and political opponents of Assad, has repeatedly said talks cannot begin until air strikes are halted, government sieges of rebel held territory are lifted and detainees freed, steps outlined in the Dec. 18 U.N. resolution.

“We want to realize pure humanitarian matters. They are not preconditions. It is an international resolution at least part of which must be implemented, so we see there is seriousness and good will in this matter,” Muslat said on Saudi-owned Arabic news channel Arabiya al-Hadath.

“Unfortunately, it is not possible to sit and talk to anyone without the suffering being lifted first.”

The lead negotiator appointed by the HNC told Reuters on Sunday the opposition was coming under pressure from Kerry to attend the talks before those demands were met.

Muslat said talks with Kerry had been “positive” and the opposition was “sticking by certain principles, not putting up obstacles.”