Human rights activists in Colombia say they are being gunned down by hitmen who can be hired for as little as $100, a top United Nations official said on Monday. A peace deal in Colombia signed two years ago that ended the nation's half-century civil war has led to a 40 percent decline in the overall murder rate, but killings of activists have risen, Michel Forst, the U.N. special rapporteur on human rights defenders said. According to a July report by British-based campaign group, Global Witness, nearly four land and environmental activists were killed each week last year, in the deadliest year on record, with Latin America faring the worst. "In rural areas ... men and women (human rights) defenders are an easy target for those who see in them or in their human rights agenda an obstacle to their interests," Forst said in a statement after a 10-day visit to Colombia. Activists working on human rights and land rights, those defending LGBT+ rights and community leaders from Afro-Colombian and indigenous groups, are most at risk, Forst said. "I was really appalled by what I heard from them," Forst, who met with more than 200 activists across Colombia, told reporters in the capital Bogota. Forst noted that just during his 10-day official visit, four activists had been murdered. Forst said he was also concerned to hear testimonies from Afro-Colombian activists who claimed attacks on them may have directly or indirectly involved foreign companies operating in Colombia, mainly those from the extractive sector.