Law enforcement officials in Colombia claim they recently uncovered a possible plot to assassinate President Ivan Duque. According to Reuters, Colombia’s Foreign Minister Carlos Holmes Trujillo went public with the information via a video message on Saturday. In the video, Trujillo described the plot as “credible” and stated three Venezuelan nationals, who are now suspects, had been arrested for possessing “weapons of war.” The weapons are being described as rifles chambered in 5.56.

“Intelligence investigations into possible attacks have been going on for several months,” said Trujillo in the video, according to Reuters. “Added to that is the recent capture of three Venezuelan citizens found in possession of weapons of war, which further increases concerns.”

Tensions between the two neighboring South American nations have been rising ever since Venezuela’s economy began to collapse several years ago. As a result of the worsening conditions in Venezuela, large numbers of the country’s population have been illegally entering surrounding states. The mass influx of people — many of which are starving and have complex medical issues — has created a humanitarian crisis. Earlier this year, the United States deployed one of its two hospital ships — the USNS Comfort — to the region to assist allied nations in caring for the migrants.

“The countries in the region are developing countries, we can’t forget that,” said Simón Bolívar University’s migrant expert Claudia Vargas Ribas during an interview with the BBC. “So receiving this quantity of people has made their internal affairs more complicated.”