Amr Moussa, the Arab League secretary-general, is expected to arrive in Damascus, the Syrian capital, on Friday to meet Arab leaders as part of his Lebanese mediation efforts.
He arrives from Beirut where he brokered a meeting between rival Lebanese leaders on Thursday.
Saad Hariri, the governing coalition leader, and Michel Aoun, the Christian opposition leader and negotiator, were brought together to try to end the country's 15-month-old political crisis.
The meeting, however, failed to resolve any disputes, a political source told the news agency Reuters.
It was the first time in three months that the two leaders had met.
Amin Gemayel, the former Lebanese president and prominent Christian leader, who is aligned with the governing majority, also took part in the three-hour talks in the parliament building in Beirut.
Discussions centered around the an initiative to elect a new president and the formation of a national unity government.
Dialogue required
"There were some agreements on some topics and this makes me optimistic that there is wide room for [fuller] agreement," Moussa later said.
"But there are some matters which require dialogue between the parties."
He is due to return to Beirut from Damascus to continue his mediation.
Political crisis has engulfed Lebanon since the post of the country's presidency fell vacant in November.
Although both sides have agreed on who should become president - General Michael Suleiman, the army chief - the division of power in a new coalition government has not been established.