Over the weekend, Syria's Arab and Kurdish rebels had their most serious confrontation since the uprising started 19 months ago.
About 16 people were killed in skirmishes between Free Syrian Army fighters and Kurdish militias in Aleppo's Kurdish-majority neighbourhood of Ashrafiyyah. In a video recorded on Saturday, hundreds of Kurdish demonstrators were shown chanting for freedom and the unity of Syrians - and at the same time, they protested against the presence of the FSA in their neighbourhood.
FSA fighters claimed that residents had asked them to retake the area; Kurdish residents, however, say FSA fighters fired on protesters, which sparked the broader fighting.
The rift between Arab and Kurdish groups has steadily widened for months. In September, Kurdish militias announced that they had seized control of Kurdish-majority areas of the country. Adnan Arour, a Saudi-based Salafi cleric who commands respect among some Sunni rebel groups, has since threatened that Kurds will suffer the consequences if they continue to occupy those areas.
Perhaps most worryingly, relations have been left to the discretion of fighters on the ground on both sides - political leaders in the various opposition camps have done almost nothing to actually lead.
The latest fighting is an alarming sign, possibly, of things to come. The clashes are essentially a result of miscommunication between the various groups acting without leadership. Some factions of the FSA believe that Kurdish groups are seeking to separate from Syria and are pre-emptively trying to stop them. Some rebels even claim that Kurdish groups - such as the PYD, which is allied with the PKK rebel group in Turkey - are collaborating with the regime, although they have no evidence.
Given Syrian Kurds' history of persecution by the regime, widespread Kurdish collaboration seems unlikely.
The danger of the recent violence is that it plants the seeds of future enmities. Arab and Kurdish issues can be solved through talks - trying to resolve them now, in the middle of the chaos, is putting the cart before the horse. There will be time enough after the Assads are gone.
Instead of trying to repair the damage, Arab and Kurdish parties have been playing the blame game. Preliminary reports yesterday indicated that insurgents on both sides had agreed to a ceasefire, but that is not enough. Violence within the ranks of rebel groups only serves their common enemy.