Most recently, Agnes-Mariam surprised reporters in late October by appearing in her black habit and white wimple outside the rebel-held town of Moadamiyeh, where she brokered a truce allowing residents to be evacuated from the besieged area.
Agnes-Mariam said she got involved after seeing photographs of starving Moadamiyeh children on her Facebook feed. "I said, 'This doesn't happen in Syria,'" she said.
The nun contacted other government and security officials she knew from decades of interfaith outreach. She said she gradually built up her connections through her "pushy" personality and constant lobbying, saying people found it hard to refuse a nun.
The truce failed several times, but over a series of days, some 5,000 people were evacuated.
Activist Qusai Zakariya, however, accused of nun of breaking her word by allowing Assad's security forces to seize men suspected of being armed rebels as they left. Zakariya said she bears responsibility for their fate if they were tortured or killed in custody.
The nun said the men were taken to determine their status as civilians or fighters. She said that two men disappeared but that volunteers were trying to locate them.
George Kallas, an official at the Beirut-based Greek Catholic Patriarchate, which oversees Agnes-Mariam's convent, would not comment directly on her work and said her statements do not reflect the opinion of the Greek Catholic Church.
Agnes-Mariam is now on a speaking tour of the U.S., Canada and Britain. But she withdrew from an anti-war conference in London this weekend after other speakers threatened to quit if she participated.
In Britain's weekly Spectator, one writer called her "the Syrian equivalent of one of Hitler's brown priests." Bouckaert of Human Rights Watch said she "abuses her religious status to spread her lies."
To others, she is a humanitarian who is informing the West by correcting biased media reporting.
"She is searching for the truth about what is happening in Syria," said Damascus-based freelance reporter Safa Mohammed.
For her part, the nun said she is doing her flawed best.
"I am not the awaited-for Messiah," she said. "I am trying to work as a human."
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