Burma's government has signed a ceasefire deal with Karen rebels, officials have told the BBC.
The agreement came at talks between officials and the Karen National Union (KNU) in Hpa-an, capital of eastern Karen state.
Both sides agreed to a ceasefire, to open communication offices and to allow passage through territories, a government official said.
The Karen have fought for greater autonomy for more than 60 years.
David Htaw, a KNU leader at the talks welcomed the accord, the first written ceasefire agreement in 63 years, but added: "Talks only go so far. What matters is practical steps taken on the ground".
A ceasefire is only a first step towards a durable peace, but it is a crucial sign of a new determination on both sides to try to resolve a bitter, decades-long conflict, says the BBC's South East Asia correspondent Rachel Harvey.
It is not clear what, if any, concessions have been made to reach this truce, our correspondent adds.
On Thursday, Burmese state television announced another prisoner amnesty, to begin on 13 January. Some 600 inmates have been identified as eligible for release by the Burmese president but it is not known if any political prisoners are among them.
The government has negotiated ceasefires with 17 other insurgent groups since 1989.
Last year, talks were held near the Thai-Burma border with several ethnic groups, including the Shan and Karen.
In December 2011, a deal for a ceasefire was reached between the local government and another major ethnic rebel group, the Shan State Army-South.
Efforts to end conflict are part of a larger bid by the military-backed nominally civilian government that came to power in November 2010 after Burma's first elections in 20 years.
This is one of the key demands of Western governments before sanctions that have been imposed on Burma can be lifted.
The peace talks in Hpa-an were led by Railway Minister Aung Min, who is also the leader of the State Peace Deal Commission, and by General Mutu Saipo of the KNU.
Aung Min told the BBC that one of the agreement's key points was that the talks would continue. Within 45 days the talks are due to reconvene for more substantive discussions.
"This is the first stage, in which we signed an agreement at state level. This allows both sides to open liaison offices and for them to travel freely without carrying arms. We also agreed [a] time and place for next stage peace talks at national level," he said.
Civil unrest has flared since the country's independence from Britain in 1948. The fighting has displaced thousands of ethnic minority members, many of whom have fled across the Thai border.
There are still tens of thousands of refugees living in camps in Thailand.
The ultimate goal of a long-term peace agreement between the government and all the ethnic groups could still take some time to materialise.
In the Kachin state, another ethnic rebel area, there continues to be reports of clashes, even though President Thein Sein has issued an order to cease fighting.