With around one week remaining until the Syria peace conference, known as Geneva 2, kicks off in the Swiss city, the United States and Britain are pressing the Syrian Opposition Coalition to attend the talks, warning the coalition that they may stop supporting them to the extent they have if they fail to show up.
This according to a senior official from the coalition, who asked not to be named.
He added other countries like France, Saudi Arabia and Turkey asked the coalition come, but in a less assertive tone.
Washington and London's stronger demand comes after the "Friends of Syria", an international group who oppose Syrian President Bashar al-Assad, called for the Syrian opposition's attendance during a meeting in Paris on Sunday.
Earlier the rebels had said they would only attend if President Assad plays no role.
The coalition says it will decide on its participation by Friday.
The Assad regime has already submitted its list of attendees.
It's also unclear whether Iran, which has a major influence in Syria, will attend, with deep divisions among world powers on that subject.
The U.S. and Britain say Iranian delegates can come to Geneva if they accept the call for a power transition away from the Assad regime, but Russia wants Iran there whatever the conditions.
This according to Russian Foreign Minister Sergei Lavrov who held talks with U.S. Secretary of State John Kerry in Paris on Monday.
Lavrov and Kerry were joined by UN envoy for Syria, Lakhdar Brahimi, where the three officials also talked about possible preconditions ahead of the peace talks.
"But we talked today about the possibility to encourage a ceasefire, maybe a localized ceasefire beginning with Aleppo and both of us have agreed to try to work to see if that could be achieved."
Possible prisoner exchanges and opening humanitarian access to besieged areas were discussed too, with the aim of creating a better atmosphere in Geneva.
Kwon Soa, Arirang News.