The Palestinian PM Ismail Haniya has said he hopes a meeting with President Mahmoud Abbas will lead to a government of national unity being formed.
Mr Haniya said there is no choice but to reach agreement in Mecca
Mr Haniya's Hamas and Mr Abbas's Fatah factions have been locked in a bitter power struggle over the last year.
Mr Abbas is meeting Mr Haniya and the supreme leader of Hamas, Khaled Meshaal in Mecca, Saudi Arabia.
The talks follow days of fighting between the two factions in the Gaza Strip that have killed at least 23.
The tensions between Hamas and Fatah have taken the Palestinians to the brink of civil war, says the BBC's Alan Johnston in Gaza.
The two delegations are going to Mecca to try to end the factional violence and work towards agreement on a government of national unity.
A shaky ceasefire on the Gaza Strip has been holding since Saturday after the latest round of violence flared on Thursday.
At least 80 people have been killed since December, about 60 of them since 25 January alone.
A shaky ceasefire has held since Saturday after days of fighting
"There may be obstacles but we confirm that we are going with true intentions to reach a Palestinian-Palestinian agreement that would end tensions and reinforce national unity," said Prime Minister Haniya.
He said they had no choice but to reach an agreement.
Replacing the current Hamas government with a more moderate coalition that draws together Hamas and Fatah might enable the Palestinians to re-engage more fully with the West, says our correspondent.
Hamas has so far refused to recognise Israel or renounce violence - both preconditions to end a crippling Western aid boycott of the Hamas government.
Most of the Palestinians' Arab neighbours - Egypt, Syria and Qatar - have brokered talks between the factions without success.
This time, the hope is that meeting in the auspicious surroundings of Islam's most holy city with the mediation of the politically and financially influential Saudi monarchy might achieve a breakthrough, says our correspondent.