Thomson Reuters Foundation

Colombian President Juan Manuel Santos spoke out on Monday to condemn the nation's soaring violence against human rights leaders amid growing pressure that the government act more forcefully to end the bloodshed.

Activists are being gunned down at a rate of one every three days in the Latin American country, rights groups say, and last Friday thousands of Colombians held protests and candlelight vigils to call for the killings to stop.

The violence follows a 2016 peace deal that ended the nation's half-century of civil war but left a power vacuum in regions where rebel fighters left and crime gangs and drug traffickers have stepped in, the United Nations has said.

Activists working on human rights and land rights, along with Afro-Colombian and indigenous people, are most at risk, campaigners say.

"I reiterate my absolute and categorical rejection of the murders and attacks against those who have been victims," said Santos, who leaves office next month.

"We must all reject and condemn this criminal phenomenon and multiply our efforts to protect them in an effective way," he said.

Santos called on the nation's political parties and judiciary to sign an agreement to protect activists.

So far this year, 123 activists have been killed, 30 more than during the same period last year, according to Indepaz, a Bogota-based think tank.

From January 2016 to last month, 311 rights activists have been murdered, Colombia's human rights watchdog, The Ombudsman, reports.

Community leaders who speak out against human rights abuses and land rights campaigners are targeted by criminal groups who see their economic and political power threatened, experts say.

"These are independent, unarmed voices in regions that are in dispute between armed groups and even just traditional landowners," Adam Isacson, a security policy expert at the Washington Office on Latin America thinktank, told the Thomson Reuters Foundation.

Rights group Amnesty International said the violence faced by activists in parts of mainly rural Colombia is "relentless".

"The discriminate violence against people defending collective rights is now widespread and constitutes a massive human rights violation," Erika Guevara-Rosas, Amnesty's Americas director, said in a statement.

"The slow implementation of the Peace Agreement in the areas worst affected by the armed conflict and the absence of the state enables armed actors to coopt territories and keep killing human rights defenders with impunity," she said.

The peace agreement was signed by the Colombian government and the left-wing rebel Revolutionary Armed Forces of Colombia (FARC).

Stemming violence in regions once controlled by the FARC is considered a key challenge facing the incoming government of conservative Ivan Duque, who takes office on 7th August.

Duque condemned the violence last week, tweeting: "As the president of Colombians, I will work intensely for the protection of social leaders."