BEIRUT: Syria's opposition chief Ahmed Moaz al-Khatib, a man prepared to take political risks to stand by his convictions, has surprised both his allies and President Bashar al-Assad's regime by offering dialogue.

Khatib, who will be 53 this year, is stylish and intellectual in appearance, wearing a short beard and Western suits, and speaks with calm determination.

He returned from Qatar to Syria to join the revolt that broke out against Assad in March 2011, in contrast with many other dissidents who remained in their adopted countries of exile.

Nearly two years on, at least 60,000 people have been killed in the civil war, the UN says, and the opposition has frequently used the term "murderer" to describe Assad.

But moderate Islamist Khatib's language has been more measured and conciliatory.

On Monday, he appealed to Assad, saying: "Look into the eyes of your children and you will recover some of your humanity. We can help each other in the interest" of the Syrian people.

Detractors immediately disqualified his offer as traitorous, and leading members of the opposition called the rhetoric "incoherent," according to Saudi Arabia's London-based Al-Sharq al-Awsat newspaper.

Khatib rejected the accusations. "I cannot accept that those who talk about negotiations are accused of treason," he said Monday.

Born in 1960 to a family of prominent religious scholars, Khatib pursued a diverse range of academic disciplines, studying geophysics, political science, international relations and diplomacy, and Islamic studies.

He joined the Syrian geology and psychology societies.

From 1985 to 1991, he worked as a geophysics engineer at Al-Furat petrol company, a joint Syrian-international venture which has included Anglo-Dutch Shell.

In 1990, he succeeded his father, Sheikh Badr al-Din al-Khatib, as imam in the prestigious Umayyad mosque in central Damascus.

But the regime banned him from speaking there after his outspoken addresses.

Khatib studied Islamic sharia (law), dawa (preaching) and rhetoric at the Islamic Institute in Damascus. He has lectured on Islam in Nigeria, Bosnia, Britain, the United States and the Netherlands.

The father of four returned from a life abroad to Syria to support the revolt when it broke out in 2011. He was closely involved in the uprising in the strategic Eastern Ghuta area, east of Damascus, for which he was arrested several times by the security services.

In June 2012, he left Syria and has based himself in Cairo.

The choice of Khatib in November 2012 to head the main opposition Syrian National Coalition, which is now recognised by many governments as the sole representative of the Syrian people, surprised the international media, but activists near Damascus who already knew him were overjoyed.

"We trust Sheikh Moaz al-Khatib as a person. He is Islamist and moderate at the same time. He has been respected for years. He came to Douma several times to participate in prayers for the revolution's martyrs," Abu Nadim, an activist in Douma, east of Damascus, told AFP via the Internet.

On January 30, Khatib responded to criticism of his call for dialogue with Damascus, denouncing those who "stay seated, do nothing, and (urge others to) attack and not negotiate."

"Some have told me that men of politics do not talk this way... I say to them: I am just a revolutionary," Khatib said on his Facebook page.

Though it is unclear whether there will be a positive response to his proposal from the Assad regime, his conciliatory rhetoric has paved the way for meetings with top Russian and Iranian officials.