Aoun stirred controversy in Lebanon when he attended a Syrian mass commemorating Lebanese Christian St. Maron, the patron saint of the Maronite Christian sect in Lebanon, Emirati newspaper The National reports.
The former prime minister was routed from office by Syrian forces in 1990 in the dying phases of the Lebanese civil war. He spent the next 15 years in exile in France only to later return to politics and pledge allegiance to Syrian ally Hezbollah in 2006.
His supporters argue the controversy shows Lebanon has yet to recover from years of acrimony with the Syrian regime.
Syrian influence loomed large in Lebanese political affairs until the fallout from the 2005 assassination of former Lebanese Prime Minister Rafik Hariri sparked reforms.
His son, Prime Minister Saad Hariri, visited Damascus in December in a show of friendship.
The Christian community in Lebanon is divided, however, and the Lebanese political environment is highly fluid.