Philippine President Benigno Aquino has hailed a power-sharing deal with Muslim rebels but warned that "contentious" issues still needed to be resolved.
The accord with the Moro Islamic Liberation Front (MILF) paves the way for ending a four-decade conflict that has claimed more than 100,000 lives.
The deal creates an autonomous region in the south with key local powers.
However, rebels must still be persuaded to lay down weapons, and other militant groups remain outside the accord.
The agreement, signed on Sunday, will set up a new autonomous region in the south that will have a democratically elected government expected to be led by the MILF - the country's largest Muslim rebel group.
It will have power over trade and investments, while the central government will remain in charge of defence, foreign and monetary policies.
But the BBC's Jennifer Pak in Malaysia, where the negotiations have been facilitated, says the next step will be a tougher one - to get rebels to lay down their weapons.
She says analysts have told the BBC the agreement was also only possible because negotiators set aside the sensitive issue of who controls the waters in the region.
President Aquino accepted that persuading the rebels to give up their weapons would be a "heavy and contentious" issue.
He said: "This is not going to be simple because here we would have to demonstrate our full trust in each other."
There are also a number of other militant groups in the south not party to the deal.
Members of the Moro National Liberation Front (MNLF) attacked the city of Zamboanga in September sparking three weeks of fighting that left dozens dead.
Analysts said the group's leader, Nur Misuari, was angry because his faction has been sidelined in the peace talks.