Al-Khatib was chosen in November to head the Syrian National Coalition, a new umbrella group designed to represent most of the rebels and soothe Western concerns about the ability of the opposition to pull together and present a viable alternative to Assad's rule.
His offer to talk to regime officials threatened to fracture the opposition once again. After an outcry, al-Khatib said he was just expressing his own opinion.
Last week the Syrian government said that opposition figures would be allowed safe return to Damascus for "national dialogue" talks an offer rejected by most opposition leaders. The government suggestion followed a recent speech by Assad in which he proposed a peace initiative that includes national dialogue and a new government and constitution.
The proposal was almost unanimously rejected by the opposition.
In his surprise turnabout, al-Khatib said he was willing to talk with representatives of Assad's regime "in Egypt, Turkey or Tunisia" on condition the government releases tens of thousands of political prisoners and renews all expired passports held by Syrians abroad a reference to exiled opposition leaders and activists who have been stripped of their Syrian passports.
There was no immediate government response to the comments by al-Moaz, a 52-year-old preacher-turned-activist chosen to head the coalition as a unifying figure.
Al-Moaz's statements, posted on his Facebook page, were later taken down and replaced by another posting in which he clarified he would be negotiating a transitional phase "to prevent more bloodshed" and asserting that he was expressing his personal opinion.
"There are those who sit on their couches and say ... do not negotiate. We don't negotiate about the regime remaining, but for its departure at the lowest cost in blood and destruction," he wrote.
The Syrian National Council, the largest group in the coalition, said al-Khatib's statements do not reflect the position of the coalition, which refuses to negotiate with a "criminal regime."
"No dialogue with the butchers," Suheir Atassi, a senior member of the coalition, wrote on her Twitter account.
Still, the opinion expressed by al-Khatib marked the first opening for the possibility of dialogue to end a nearly two-year-long conflict that the U.N. says has killed more than 60,000 people.
Al-Khatib's statement came a day after the international peace envoy for Syria gave a bleak briefing to the U.N. Security Council.
Lakhdar Brahimi suggested that the Security Council revisit the Geneva Communique of June 2012, a broad but ambiguous proposal endorsed by the Western powers and Russia to provide a basis for negotiations.
Assad's role in a transition government was a main bone of contention during the negotiations toward drafting the Geneva Communique, and it was left vague. The United States and Russia continue to disagree on Assad's role, though both signed off on the communique.
The outline has yet to lead to meaningful progress to end the civil war.