Colombian President Juan Manuel Santos said his government may reach an agreement on a bilateral ceasefire with leftist rebels as early as this week.

Santos said at an event in Bogota on Tuesday that both sides are very close to an agreement and that hopefully one could be reached this week.

A government official, speaking on condition of anonymity in line with official policy, said Santos will travel to Cuba to announce on Thursday a blueprint for the Revolutionary Armed Forces of Colombia's disarmament. The official said the United Nations' Secretary General Ban Ki-moon is expected to attend.

The president's team of peace negotiators wouldn't comment on any possible deal or Santos' travel plans.

Talks to end Colombia's bloody half-century war have been taking place in Havana for four years.