The Burmese government has signed a ceasefire agreement with eight ethnic rebel armies, but the more powerful groups have refused to come on board.
The agreement was signed at a ceremony in the administrative capital, Naypyitaw.
The refusal of the larger groups to sign it robs president Thein Sein of what he had hoped would be the crowning achievement of his five-year term.
It is still seen as a first step toward ending six decades of fighting between the government, dominated by the Burmese majority, and various minority ethnic groups demanding autonomy and control over their natural resources.
Ethnic groups, representing 40% of the 53 million population, have found themselves victims of military abuses and discrimination in areas spanning from health and education to road construction and access to electricity.
"The National Ceasefire Agreement is a historic gift from us to the generations of the future," Thein Sein said at the signing ceremony.
"Even though the agreement is not nationwide yet, we will try harder to gain the agreement with other groups."
Burma stunned the world by opening up politically and economically in 2011 after half a century of harsh military rule, but early reforms have since stalled or started rolling backward.
That has upped the stakes for getting ceasefire deals with all ethnic armies, one of Thein Sein's biggest pledges.
It comes just before November 8 general elections for a new parliament, which will eventually lead to the election of a new president.