The Revolutionary Armed Forces of Colombia (FARC) has accused the Colombian government of harassing relatives of a senior rebel, highlighting tensions without disrupting a third day of peace talks in Havana, Cuba.
Viviana Hernandez, a FARC spokeswoman, read out a statement on Wednesday alleging that Colombian police had threatened the relatives of unit commander Francisco Gonzalez as they sought information about his whereabouts.
"Members of the police, disguised as civilians, are pressuring the family to prosecute and take custody of their young children unless they reveal information" about his location, Hernandez said.
She read her remarks during the third day of peace talks with a government delegation at a convention centre in Havana.
Despite the development, Ivan Marquez, a leading FARC delegate, expressed optimism about the outcome of the dialogue, which is expected to run into next week, before entering the closed-door talks.
"I'd like like to say that we are working hard for peace," Marquez said.
"We have immense faith in the ability of the Colombian people to achieve the peace that we all so deeply yearn for."
Negotiations aimed at ending Latin America's longest-running rebellion began on Monday with the FARC declaring a unilateral two-month ceasefire, after a preliminary round of talks last month in Norway.
Colombian President Juan Manuel Santos has stressed that his government is not yet bound by the ceasefire and that military operations against the FARC will continue until a deal is brokered.
The FARC, which was founded in 1964 and is believed to have about 9,000 armed fighters, took up arms to protest the concentration of land ownership in Colombia.
Several top commanders have been captured or killed in recent years as the group has suffered a string of military defeats and its ranks have been severely depleted since the FARC's peak in the 1990s.
In addition to the issue of land ownership, both sides must agree on a plan to end hostilities, on how to incorporate the FARC into the political realm, on how to curb drug trafficking, and on how to compensate victims of the conflict.
Both sides have expressed confidence that an end to the decades-long conflict that has claimed hundreds of thousands of lives is within reach.