Donald Trump's one-time rival for Presidential nominee has used his role on the Senate to speak against China's ongoing persecution of Christians.
The Florida senator highlighted the cases of two detained human rights attorneys, Jiang Tianyong and Tang Jingling.
Jiang's wife last heard from him almost four months ago when he disappeared after visiting another lawyer who had been jailed. He boarded a train home on November 21 but never arrived, according to persecution charity China Aid.
Officials later announced he was being held at a undisclosed location and has not been allowed visits from his lawyer or family since.
Tang was one of dozens arrested in the build up to the 25th anniversary of the Tiananmen Square massacre. The 1989 protests were marked in June 2014 and Tang was detained beforehand on suspicion 'inciting subversion of state power'. In January 2016, he and two other prisoners of conscience were tried, and Tang was sentenced to five years in prison.
Rubio urged White House officials to take up these and other cases with their Chinese counterparts.
He said: "Inside the grand edifice of the court, we can see stately and ornate furnishings and decorations, and we can see the government employees in dignified attire. But we cannot see the law and we can definitely not see justice."