Colombian President Gustavo Petro said he has considered barring U.S. Deputy Secretary of State Christopher Landau from entering the country, underscoring a rapid deterioration in relations with Washington following the assassination of opposition senator Miguel Uribe Turbay. Landau is scheduled to arrive in Bogotá on Tuesday night to attend the senator’s funeral, which Petro described as a national day of mourning. Uribe Turbay, 39, died on 11 August after spending two months in a coma caused by gunshot wounds sustained during a campaign rally. Colombian prosecutors have arrested six suspects and are investigating whether dissident FARC factions ordered what they classify as a “magnicidio.” Landau said his visit is meant to convey the United States’ “intense concern” about political violence in its long-time ally. Petro told military officers that Landau had insulted him by labeling him a “communist,” adding that he had “thought about” refusing the diplomat entry but would “not behave like them.” The remarks follow criticism from U.S. Secretary of State Marco Rubio, who called Petro’s leadership “erratic,” and come as a bipartisan U.S. congressional delegation led by Senators Bernie Moreno and Rubén Gallego prepares to meet Petro in Bogotá later this week. Regional tensions are rising on another front after Venezuelan President Nicolás Maduro publicly urged the creation of a joint force between the Venezuelan and Colombian militaries. Petro denied talk of a merger but welcomed closer coordination against narcotrafficking along the border, a stance that has fueled additional criticism from Colombian opposition figures and U.S. officials. Thousands of Venezuelans and allied social movements mounted demonstrations in Caracas and several Colombian cities on Monday, accusing the Trump administration of “imperialist aggression.” The White House last week offered a $50 million reward for information leading to Maduro’s capture over alleged drug-trafficking ties.