Palestinian President Mahmoud Abbas and Hamas chief Khaled Meshaal have met for the first time since their rival factions signed a surprise unity deal.
"The meeting has started," a source in Abbas's Ramallah office told the AFP news agency about the meeting in the Qatari capital Doha on Monday.
Abbas had arrived in Doha the previous day. Meshaal, the exiled Hamas leader, has been based in Doha for more than two years after he left his previous base in Damascus because of the bloodshed gripping Syria.
The last time the two leaders had met face-to-face was in Cairo in January 2013.
Hamas spokesman Sami Abu Zuhri said at the weekend that the two leaders were expected to "discuss the reconciliation agreement and how to implement it".
Abbas's Fatah movement, which dominates the Palestine Liberation Organisation and rules the West Bank, has been locked in years of bitter rivalry with Meshaal's Hamas.
But on April 23, the PLO and the Hamas announced they had reached a deal under which they would work together to form a new national consensus government.
News of the deal provoked an angry response from Israel, which said it would not negotiate with any Palestinian government backed by Hamas, putting the final nail in the coffin of the stalled US-brokered peace talks.