Colombian President Juan Manuel Santos has won the 2016 Nobel Peace Prize, in a surprise choice after Colombians voted "No" to an agreement he signed with Marxist rebels to end 52 years of war.

Mr Santos has promised to revive the peace plan even though Colombians, in a referendum last Sunday, narrowly rejected the accord.

Many voters believed it was too lenient on the FARC guerrillas.

"The award should also be seen as a tribute to the Colombian people," committee leader Kaci Kullmann Five said when announcing the prize.

Voters did not say "No" to peace but to the agreement, she said.

The award pointedly excluded FARC guerrilla leader Rodrigo Londono, better known by his nom de guerre Timochenko, who signed the deal with Mr Santos.

This afternoon, the head of Colombia's FARC rebels congratulated Mr Santos for winning the prize.

"I congratulate President Juan Manuel Santos, Cuba and Norway, who sponsored the process, and Venezuela and Chile, who assisted it," FARC leader Rodrigo Londono, alias Timoleon "Timochenko" Jimenez, wrote on Twitter.

"Without them, peace would be impossible."

Some Nobel watchers had taken Colombia off their lists of favourites after the referendum "No".

"The fact that a majority of the voters said "No" to the peace accord does not necessarily mean that the peace process is dead," the committee said.

"This makes it even more important that the parties, headed by President Santos and FARC guerrilla leader Rodrigo Londoo, continue to respect the ceasefire," the committee said. 

The Nobel Peace Prize, worth eight million Swedish crowns (€832,000), will be presented in Oslo on 10 December.

President Michael D Higgins has congratulated Mr Santos, saying in a statement: "The decision by the Nobel Committee to award the Nobel Peace Prize to President Santos for 'his resolute efforts to bring the country's more than 50-year-long civil war to an end' is both welcome and deserved.

"The award is also a recognition and encouragement for all those in Colombia and further afield who are seeking to resolve conflict through peaceful means."