Syria's ruling Baath Party has expelled former Vice-President Abdul Halim Khaddam - a day after parliament voted to bring treason charges against him.
Khaddam (r) was at the heart of Syrian politics until he resigned in June
The moves follow remarks by Mr Khaddam implicating President Bashar al-Assad in the murder of former Lebanese Prime Minister Rafik Hariri in February 2005.
The remarks in an Arabic TV interview have caused outrage in mainstream political circles in Damascus.
A UN-led inquiry implicated Syria in the murder, but Damascus denies blame.
Top Syrian officials are among 19 suspects a UN report says have been identified over the huge bomb attack in Beirut that killed Mr Hariri.
The attack sparked such public outrage that Syria was eventually forced to end decades of military presence in Lebanon.
Mr Khaddam, at the heart of Syrian politics for more than 20 years, resigned from his post in June 2005, and went to France with his family.
"The national leadership has decided to throw Khaddam out of the party. It considers him a traitor," a Baath Party statement said.
"Khaddam has betrayed the party, the homeland and the (Arab) nation."
It added that his comments to al-Arabiya TV broadcast on Friday were "a slander which violates the principles of the nation."
Mr Khaddam told al-Arabiya television: "Assad told me he had delivered some very, very harsh words to Hariri... something like 'I will crush anyone who tries to disobey us'."
President Assad has previously denied any personal involvement in the murder.
On Saturday, the Syrian parliament unanimously backed a motion pressing the justice minister to bring proceedings against Mr Khaddam for high treason.