CARACAS, Venezuela (AFP) — An Italian, a Swiss and a Venezuelan journalist have been arrested as they prepared a report on a prison in northern Venezuela, human rights and press freedom groups said.

Roberto Di Matteo of Italy, Filippo Rossi of Switzerland and Jesus Medina of Venezuela were arrested Friday after entering Tocoron prison in northern Aragua state with a television crew, according to the rights group Foro Penal.

The national journalists union said the trio were conducting a “media investigation” when they were arrested.

Critics say Venezuelan prisons are overpopulated and inmates are malnourished, despite government plans to reduce inmate populations.

The Swiss foreign ministry said the Swiss embassy in Caracas “is in contact with the appropriate authorities and is assisting this Swiss national in accordance with the consular protections afforded him.”

The Italian foreign ministry said its mission “has been following from the very beginning the arrest of Italian national Roberto Di Matteo, and is in close contact with local authorities.”

Di Matteo works as a videographer for Italian daily newspaper Il Giornale, regularly collaborating with independent journalist Rossi, the publication said on its website.

Rossi had also worked with regional Swiss daily Corriere del Ticino, while Medina is a photojournalist for anti-government website DolarToday.

The union released a photograph of the three journalists taken from the back, apparently handcuffed and escorted by two military personnel. Their cellphones and small cameras were confiscated.

Union representatives told AFP the journalists were in good health late Saturday.

“They are doing well and show no signs of mistreatment,” according to the SNTP union.

“They had an invitation to enter Tocoron. They had registered to enter when they were barred access and then arrested. It seems there was a counter-order to bar them access.”

Foro Penal director Alfredo Romero said some of his group’s lawyers had traveled to provide legal aid to the trio, who are being held by national police.

Late last year, rights group Una Ventana a La Libertad estimated that there are some 88,000 inmates across a country with an official prison capacity of 35,000.

President Nicolas Maduro’s government, which says it is being unfairly disparaged in national and international media, says it has successfully applied measures to pacify prisons and raise their standards to international norms.