The civil war in Syria appears to be getting even more messy, if that's possible to believe.
Reuters news agency reported that volunteers from Iraq and Lebanon have formed a militia brigade and are fighting to protect a Shi'ite holy place near Damascus, the Sayyida Zaynab Shrine.
That's pitting them against Syria's predominantly Sunni rebels.
The sectarian fighting has echoes of the Sunni-Shi'ite violence that dominated the middle years of the war in Iraq.
And it comes at a time when Shi'ites are feeling under siege from Lebanon to Pakistan.
Vali Nasr believes these volunteers are sincere in wanting to protect the Shrine.
Nasr is dean of the Johns Hopkins School of Advanced International Studies in Washington.
"Other shrines have been attacked in the past, notably in Samarra, Iraq, in 2006," says Nasr. That attack triggered a horrific sectarian war, with US troops caught in the middle.
However he adds that Hezbollah in Lebanon, and the government of Iraq, could well be sending in proxies to support the Syrian government directly.
Sunni jihadis are already fighting to support the rebels.
"It's an international conflict," says Nasr. "The outcome will change the balance of power between Sunnis and Shi'ites regionally. … This conflict is about their own sets of issues and was never just about Syria. … As the stakes have gotten higher, (regional powers) are investing more and more in trying to protect their interests and trying to decide the outcome."
Nasr also criticizes US policy for failing to appreciate this regional dimension.