Bolivia ? President Evo Morales on Monday ordered a U.S. diplomat to leave Bolivia for allegedly conspiring with opposition groups, further straining tense relations six months after he expelled the American ambassador.

The leftist leader said investigations determined that the U.S. Embassy’s second secretary, Francisco Martinez, “was in permanent contact with opposition groups.”

The U.S. State Department called the Bolivian move “unwarranted and unjustified.”

“We reject the allegations,” it said in a statement in Washington.

Martinez was a career diplomat focused on political affairs, said a U.S. Embassy official who was not authorized to discuss the expulsion and thus spoke on condition of anonymity.