Colombian President Juan Manuel Santos has confirmed his government is holding exploratory talks with the country's largest rebel group, the Farc.
In an address on state TV, Mr Santos said he was fulfilling his "duty to seek peace". Media reports say a deal on further talks was reached in Cuba.
The Farc has been fighting the Colombian government since 1964.
The president said the second biggest rebel group, the ELN, had also indicated a readiness to talk.
'Learning from mistakes'
Mr Santos gave no details about the exploratory talks with the left-wing Revolutionary Armed Forces of Colombia (Farc).
According to the regional media network Telesur, negotiators from the two sides signed a preliminary agreement in the Cuban capital Havana on Monday.
Telesur said the first round of peace talks would be held in the Norwegian capital Oslo on 5 October. Negotiators would then continue holding talks in Havana, it added.
Referring to previous failed talks with the Farc during the government of then-president Andres Pastrana, Mr Santos said his government had "learned from the mistakes committed in the past".
Mr Santos said military operations would continue and that "each centimetre of the country would have a military presence".
As part of the peace talks launched in 1998, Mr Pastrana had granted the Farc a safe haven the size of Switzerland in the south-east to help move peace talks along.
The zone was off-limits to the army and the rebels used it to train and regroup.
Mr Pastrana ordered the rebels out of their safe haven after the peace talks failed in February 2002, but part of the area remains a rebel stronghold to this day.
Last August, the Farc leader at the time, Alfonso Cano, said the group was ready for peace negotiations.
Since then, rumours have circulated about secret meetings between government representatives and the rebels in the Cuban capital.
Upon taking office just over two years ago, Mr Santos signalled his willingness to open peace talks.
He has come under severe criticism for this from his predecessor, Alvaro Uribe.
The Farc also re-stated their openness to talks in March. Following the death of Alfonso Cano in a bombing raid, the Farc's new leader, known as Timochenko, said it was "worth betting on peace".
Colombian security forces have achieved a series of successes against the rebel group in recent years, killing some of its key leaders and arresting many others.
But officials estimate that some 8,000 Farc guerrillas are still fighting Latin America's longest-running insurgency.
Referring to the ELN, Mr Santos said that if the group was serious about an end to the armed conflict, it too could be part of peace talks.
In a recent interview, ELN leader Nicolas Rodriguez said he was willing to hold negotiations but refused to end the group's campaign of kidnapping and bomb attacks ahead of any talks.
Time for talks
While it is too early to say whether this latest attempt at talks will work, it does seem as if Colombia is ready for peace, Peter Hakim from US-based think-tank Inter-American Dialogue told the BBC.
"One senses that both sides see themselves at an impasse. The guerrillas are not going to be able to do much more than... hit-and-run activities. The government, to wipe out the last group of guerrillas, it's going to be very costly," he said.
Readers contacting the BBC News website from Colombia broadly welcomed the latest developments, but many indicated that lasting peace means much more than signing any document.
"The breeding ground for these kind of organisations such as guerrillas and paramilitaries is inequality and partial, in some cases, complete absence of a state providing security, health and education to its population," wrote Javier Pardo in Bogota.
Patricia in Bogota also identified the need for the state to be present in rural areas where guerrillas hold sway.
"People in these areas need more opportunity to participate in the progress and prosperity the people in the cities are enjoying," she wrote.