The U.S. State Department has expressed concern over the welfare of a Utah man jailed in Venezuela, a day after he managed to upload a video to Facebook saying inmates at his prison had seized the complex and were trying to kill him.As we have reported previously, 26-year-old Joshua Holt traveled to Venezuela in 2016 to marry Thamara Caleno Candelo, whom he met online. Police later raided the couple's Caracas apartment, where they claimed to find an AK-47 rifle and a grenade, hauling them both off to jail.In two 20-second videos shot on a cellphone and posted on his Facebook page from Venezuela's notorious El Helicoide prison, Holt said earlier this week that he had "been begging my government for two years. They say they're doing things but I'm still here."He also said that the prison had "fallen" during a riot by inmates and people were "trying to break into my room and kill me."State Department spokeswoman Heather Nauert said Thursday that the U.S. has "serious concerns about the safety and welfare of U.S. citizens who are being held" in Venezuela."The Venezuelan government is responsible for the safety of all detainees in its prison system, including U.S. citizens in detention," she said.Nauert the State Department had been in contact with a top Venezuelan diplomat seeking Holt's release on humanitarian grounds.In February, a top-ranking Republican aide, Caleb McCarry, met with Venezuelan President Nicolas Maduro in Venezuela to discuss Holt's possible release. In the same month, Utah Sen. Orrin Hatch sent a letter to Holt in prison saying that he and others officials were working "tirelessly for your freedom."Hatch said he was "confident" that Holt's "dark chapter will close and you will soon be reunited with your family." Copyright 2018 NPR. To see more, visit http://www.npr.org/.