DUBAI, United Arab Emirates (AP) An American citizen has been arrested in Saudi Arabia, tortured and sentenced to 16 years in prison over tweets he sent while in the United States, his son said Tuesday.

Saad Ibrahim Almadi, a 72-year-old retired project manager living in Florida, was arrested last November while visiting family in the kingdom and was sentenced earlier this month, his son Ibrahim told The Associated Press, confirming details that were first reported by the Washington Post. Almadi is a citizen of both Saudi Arabia and the U.S.

There was no immediate comment from Saudi officials.

State Department deputy spokesman Vedant Patel, speaking to reporters in Washington, confirmed Almadis detention Tuesday.

We have consistently and intensively raised our concerns regarding the case at senior levels of the Saudi government, both through channels in Riyadh and Washington DC as well and we will continue to do so, he said. We have raised this with members of the Saudi government as recently as yesterday.

It appeared to be the latest in a series of recent cases in which Saudis received long jail sentences for social media posts critical of the government.

Saudi authorities have tightened their crackdown on dissent following the rise of Crown Prince Mohammed bin Salman, who is seeking to open up and transform the ultraconservative kingdom but has adopted a hard line toward any criticism.