RIO DE JANEIRO, July 13 (Xinhua) -- Brazilian Foreign Minister Aloysio Nunes on Friday criticized the U.S. separation policy towards immigrant families, saying it was a "cruel measure."

Addressing a business event, the minister said he traveled to the United States earlier this month and personally verified the situation of dozens of Brazilian children who had been separated from their parents.

The immigrant children are being kept in facilities which resemble prisons and they have no contact with their parents, Nunes said, adding that the reunification of families, which was decided weeks ago, is taking place at a very slow pace.

The cruel measure could potentially cause severe trauma to children, he added.

The family separation policy, described by the Trump administration as part of its "zero tolerance" policy, was implemented in April. It was then suspended for an indefinite period of time following widespread public opposition and pressure.