(Adds state news agency says operation successful)
BEIRUT, March 14 (Reuters) - Syrian Foreign Minister Walid al-Moualem underwent heart surgery on Friday at a hospital in Lebanon, Syrian state media said.
SANA news agency said the operation, which it described as a planned procedure, had been a success.
Moualem, 73, was admitted to the American University of Beirut Medical Center on Thursday, where coronary tests showed he needed an operation, medical sources had earlier told Reuters.
Moualem, Syria's top diplomat since 2006, led the Syrian official government delegation to peace negotiations in Geneva with representatives of the opposition who are seeking to end President Bashar al-Assad's rule.
Two rounds of peace talks mediated by U.N. peace mediator Lakhdar Brahimi in January and February failed to bring the sides closer to agreement on a transitional government or halt fighting that has killed more than 146,000 people since the conflict started in March 2011. (Reporting by Laila Bassam and Stephen Kalin; Editing by Alison Williams and Lisa Shumaker)