The US has imposed sanctions on a network it says is recruiting former Colombian soldiers and training individuals to fight in Sudan's civil war.
Eight entities and individuals - primarily of Colombian nationality - have been aiding the Sudanese paramilitary Rapid Support Forces (RSF), the US Treasury's Office of Foreign Assets Control (OFAC) said on Tuesday.
Its statement added that hundreds of Colombian mercenaries have travelled to Sudan since 2024, including to serve as infantry and drone pilots for the RSF.
Last year, Colombian President Gustavo Petro said those who "spill young blood for money in foreign countries must be punished criminally".
The participation of soldiers - both former and active - in foreign conflicts dates back decades to the US wars in Afghanistan and Iraq, in exchange for American military aid in Colombia's war on drugs and armed groups.
"This created an even greater number of Colombian soldiers who, two decades later, are beginning to retire without a sufficient source of income," a retired military officer turned academic told BBC Mundo.
Alfonso Manzur explained that as a result, "we see more Colombian ex-soldiers on missions abroad".
Retired Colombian soldiers are commonly recruited under false promises of low-risk work, before appearing on the frontlines, such as in the current conflict between Russia and Ukraine, and in Sudan.
In 2024, the Colombian foreign ministry said it was aware of citizens being deceived by what it called "sophisticated human trafficking networks", and becoming mercenaries in international conflicts.
On Tuesday, the US Treasury's OFAC said it was targeting a network for recruiting fighters for the RSF, which has been battling the Sudanese army since April 2023.
"The RSF has shown again and again that it is willing to target civilians - including infants and young children," said John Hurley, the Treasury's under-secretary for terrorism and financial intelligence.
"Its brutality has deepened the conflict and destabilized the region, creating the conditions for terrorist groups to grow."
The State Department has said the group and its allied militias have attacked civilians, systematically killed men and boys and deliberately targeted and raped women and girls.
Earlier this year, it determined that RSF members had committed genocide, although both the paramilitary group and the army have repeatedly been accused of war crimes.
The transnational network accused of aiding the group consists of four entities and four individuals, including a dual Colombian-Italian national who is a former military officer, now based in the United Arab Emirates, a country repeatedly accused of arming the RSF. It denies the allegations.
"All property and interests in property of the designated or blocked persons... or in the possession or control of U.S. persons are blocked and must be reported", the Treasury said.
The US has accused the primarily Colombian network of recruiting mercenaries to serve with the RSF, providing "tactical and technical expertise", and even training children to fight.
According to its statement, Colombian fighters were involved in "numerous battles across Sudan" including in the capital Khartoum, Omdurman, Kordofan, and el-Fasher.
On the ground, the RSF has been making gains, most notably seizing the city of el-Fasher in October, after a 500-day starvation siege.
It is estimated that more than 5,000 people were killed as the paramilitary rampaged through the army's last stronghold in Darfur.
The three states that make up Kordofan, home to almost eight million people, and situated between Khartoum and Darfur, has recently become a major frontline.
On Monday, at least 114 people, including 63 children, were killed in strikes on a kindergarten and hospital in South Kordofan, the World Health Organisation said.
WHO director-general Tedros Adhanom Ghebreyesus described the attack as "senseless" as he repeated calls for a ceasefire.
The RSF also claimed control of Sudan's largest oil field, Heglig, in what the paramilitary group hailed as "a turning point for the liberation" of the country.